PEP: 1 Title: PEP Purpose and Guidelines Author: Barry Warsaw, Jeremy
Hylton, David Goodger, Alyssa Coghlan Status: Active Type: Process
Created: 13-Jun-2000 Post-History: 21-Mar-2001, 29-Jul-2002,
03-May-2003, 05-May-2012, 07-Apr-2013

What is a PEP?

PEP stands for Python Enhancement Proposal. A PEP is a design document
providing information to the Python community, or describing a new
feature for Python or its processes or environment. The PEP should
provide a concise technical specification of the feature and a rationale
for the feature.

We intend PEPs to be the primary mechanisms for proposing major new
features, for collecting community input on an issue, and for
documenting the design decisions that have gone into Python. The PEP
author is responsible for building consensus within the community and
documenting dissenting opinions.

Because the PEPs are maintained as text files in a versioned repository,
their revision history is the historical record of the feature proposal.
This historical record is available by the normal git commands for
retrieving older revisions, and can also be browsed on GitHub.

PEP Audience

The typical primary audience for PEPs are the core developers of the
CPython reference interpreter and their elected Steering Council, as
well as developers of other implementations of the Python language
specification.

However, other parts of the Python community may also choose to use the
process (particularly for Informational PEPs) to document expected API
conventions and to manage complex design coordination problems that
require collaboration across multiple projects.

PEP Types

There are three kinds of PEP:

1.  A Standards Track PEP describes a new feature or implementation for
    Python. It may also describe an interoperability standard that will
    be supported outside the standard library for current Python
    versions before a subsequent PEP adds standard library support in a
    future version.
2.  An Informational PEP describes a Python design issue, or provides
    general guidelines or information to the Python community, but does
    not propose a new feature. Informational PEPs do not necessarily
    represent a Python community consensus or recommendation, so users
    and implementers are free to ignore Informational PEPs or follow
    their advice.
3.  A Process PEP describes a process surrounding Python, or proposes a
    change to (or an event in) a process. Process PEPs are like
    Standards Track PEPs but apply to areas other than the Python
    language itself. They may propose an implementation, but not to
    Python's codebase; they often require community consensus; unlike
    Informational PEPs, they are more than recommendations, and users
    are typically not free to ignore them. Examples include procedures,
    guidelines, changes to the decision-making process, and changes to
    the tools or environment used in Python development. Any meta-PEP is
    also considered a Process PEP.

PEP Workflow

Python's Steering Council

There are several references in this PEP to the "Steering Council" or
"Council". This refers to the current members of the elected Steering
Council described in PEP 13, in their role as the final authorities on
whether or not PEPs will be accepted or rejected.

Python's Core Developers

There are several references in this PEP to "core developers". This
refers to the currently active Python core team members described in PEP
13.

Python's BDFL

Previous versions of this PEP used the title "BDFL-Delegate" for PEP
decision makers. This was a historical reference to Python's previous
governance model, where all design authority ultimately derived from
Guido van Rossum, the original creator of the Python programming
language. By contrast, the Steering Council's design authority derives
from their election by the currently active core developers. Now,
PEP-Delegate is used in place of BDFL-Delegate.

PEP Editors

The PEP editors are individuals responsible for managing the
administrative and editorial aspects of the PEP workflow (e.g. assigning
PEP numbers and changing their status). See PEP Editor Responsibilities
& Workflow for details.

PEP editorship is by invitation of the current editors, and they can be
contacted by mentioning @python/pep-editors on GitHub. All of the PEP
workflow can be conducted via the GitHub PEP repository issues and pull
requests.

Start with an idea for Python

The PEP process begins with a new idea for Python. It is highly
recommended that a single PEP contain a single key proposal or new idea;
the more focused the PEP, the more successful it tends to be. Most
enhancements and bug fixes don't need a PEP and can be submitted
directly to the Python issue tracker. The PEP editors reserve the right
to reject PEP proposals if they appear too unfocused or too broad. If in
doubt, split your PEP into several well-focused ones.

Each PEP must have a champion -- someone who writes the PEP using the
style and format described below, shepherds the discussions in the
appropriate forums, and attempts to build community consensus around the
idea. The PEP champion (a.k.a. Author) should first attempt to ascertain
whether the idea is PEP-able. Posting to the Ideas category of the
Python Discourse is usually the best way to go about this, unless a more
specialized venue is appropriate, such as the Typing category (for
static typing ideas) or Packaging category (for packaging ideas) on the
Python Discourse.

Vetting an idea publicly before going as far as writing a PEP is meant
to save the potential author time. Many ideas have been brought forward
for changing Python that have been rejected for various reasons. Asking
the Python community first if an idea is original helps prevent too much
time being spent on something that is guaranteed to be rejected based on
prior discussions (searching the internet does not always do the trick).
It also helps to make sure the idea is applicable to the entire
community and not just the author. Just because an idea sounds good to
the author does not mean it will work for most people in most areas
where Python is used.

Once the champion has asked the Python community as to whether an idea
has any chance of acceptance, a draft PEP should be presented to the
appropriate venue mentioned above. This gives the author a chance to
flesh out the draft PEP to make properly formatted, of high quality, and
to address initial concerns about the proposal.

Submitting a PEP

Following the above initial discussion, the workflow varies based on
whether any of the PEP's co-authors are core developers. If one or more
of the PEP's co-authors are core developers, they are responsible for
following the process outlined below. Otherwise (i.e. none of the
co-authors are core developers), then the PEP author(s) will need to
find a sponsor for the PEP.

Ideally, a core developer sponsor is identified, but non-core sponsors
may also be selected with the approval of the Steering Council. Members
of the GitHub "PEP editors" team and members of the Typing Council (PEP
729) are pre-approved to be sponsors. The sponsor's job is to provide
guidance to the PEP author to help them through the logistics of the PEP
process (somewhat acting like a mentor). Being a sponsor does not
disqualify that person from becoming a co-author or PEP-Delegate later
on (but not both). The sponsor of a PEP is recorded in the "Sponsor:"
field of the header.

Once the sponsor or the core developer(s) co-authoring the PEP deem the
PEP ready for submission, the proposal should be submitted as a draft
PEP via a GitHub pull request. The draft must be written in PEP style as
described below, else it will fail review immediately (although minor
errors may be corrected by the editors).

The standard PEP workflow is:

-   You, the PEP author, fork the PEP repository, and create a file
    named pep-{NNNN}.rst that contains your new PEP. {NNNN} should be
    the next available PEP number not used by a published or in-PR PEP.

-   In the "PEP:" header field, enter the PEP number that matches your
    filename as your draft PEP number.

-   In the "Type:" header field, enter "Standards Track",
    "Informational", or "Process" as appropriate, and for the "Status:"
    field enter "Draft". For full details, see PEP Header Preamble.

-   Update .github/CODEOWNERS such that any co-author(s) or sponsors
    with write access to the PEP repository are listed for your new
    file. This ensures any future pull requests changing the file will
    be assigned to them.

-   Push this to your GitHub fork and submit a pull request.

-   The PEP editors review your PR for structure, formatting, and other
    errors. For a reST-formatted PEP, PEP 12 is provided as a template.
    It also provides a complete introduction to reST markup that is used
    in PEPs. Approval criteria are:

    -   It is sound and complete. The ideas must make technical sense.
        The editors do not consider whether they seem likely to be
        accepted.
    -   The title accurately describes the content.
    -   The PEP's language (spelling, grammar, sentence structure, etc.)
        and code style (examples should match PEP 7 & PEP 8) should be
        correct and conformant. The PEP text will be automatically
        checked for correct reStructuredText formatting when the pull
        request is submitted. PEPs with invalid reST markup will not be
        approved.

    Editors are generally quite lenient about this initial review,
    expecting that problems will be corrected by the reviewing process.
    Note: Approval of the PEP is no guarantee that there are no
    embarrassing mistakes! Correctness is the responsibility of authors
    and reviewers, not the editors.

    If the PEP isn't ready for approval, an editor will send it back to
    the author for revision, with specific instructions.

-   Once approved, they will assign your PEP a number.

Once the review process is complete, and the PEP editors approve it
(note that this is not the same as accepting your PEP!), they will
squash commit your pull request onto main.

The PEP editors will not unreasonably deny publication of a PEP. Reasons
for denying PEP status include duplication of effort, being technically
unsound, not providing proper motivation or addressing backwards
compatibility, or not in keeping with the Python philosophy. The
Steering Council can be consulted during the approval phase, and are the
final arbiter of a draft's PEP-ability.

Developers with write access to the PEP repository may claim PEP numbers
directly by creating and committing a new PEP. When doing so, the
developer must handle the tasks that would normally be taken care of by
the PEP editors (see PEP Editor Responsibilities & Workflow). This
includes ensuring the initial version meets the expected standards for
submitting a PEP. Alternately, even developers should submit PEPs via
pull request. When doing so, you are generally expected to handle the
process yourself; if you need assistance from PEP editors, mention
@python/pep-editors on GitHub.

As updates are necessary, the PEP author can check in new versions if
they (or a collaborating developer) have write access to the PEP
repository. Getting a PEP number assigned early can be useful for ease
of reference, especially when multiple draft PEPs are being considered
at the same time.

Standards Track PEPs consist of two parts, a design document and a
reference implementation. It is generally recommended that at least a
prototype implementation be co-developed with the PEP, as ideas that
sound good in principle sometimes turn out to be impractical when
subjected to the test of implementation.

Discussing a PEP

As soon as a PEP number has been assigned and the draft PEP is committed
to the PEP repository, a discussion thread for the PEP should be created
to provide a central place to discuss and review its contents, and the
PEP should be updated so that the Discussions-To header links to it.

The PEP authors (or sponsor, if applicable) may select any reasonable
venue for the discussion, so long as the the following criteria are met:

-   The forum is appropriate to the PEP's topic.
-   The thread is publicly available on the web so that all interested
    parties can participate.
-   The discussion is subject to the Python Community Code of Conduct.
-   A direct link to the current discussion thread is provided in the
    PEP under the Discussions-To header.

The PEPs category of the Python Discourse is the preferred choice for
most new PEPs, whereas historically the Python-Dev mailing list was
commonly used. Some specialized topics have specific venues, such as the
Typing category and the Packaging category on the Python Discourse for
typing and packaging PEPs, respectively. If the PEP authors are unsure
of the best venue, the PEP Sponsor and PEP editors can advise them
accordingly.

If a PEP undergoes a significant re-write or other major, substantive
changes to its proposed specification, a new thread should typically be
created in the chosen venue to solicit additional feedback. If this
occurs, the Discussions-To link must be updated and a new Post-History
entry added pointing to this new thread.

If it is not chosen as the discussion venue, a brief announcement post
should be made to the PEPs category with at least a link to the rendered
PEP and the Discussions-To thread when the draft PEP is committed to the
repository and if a major-enough change is made to trigger a new thread.

PEP authors are responsible for collecting community feedback on a PEP
before submitting it for review. However, to avoid long-winded and
open-ended discussions, strategies such as soliciting private or more
narrowly-tailored feedback in the early design phase, collaborating with
other community members with expertise in the PEP's subject matter, and
picking an appropriately-specialized discussion for the PEP's topic (if
applicable) should be considered. PEP authors should use their
discretion here.

Once the PEP is assigned a number and committed to the PEP repository,
substantive issues should generally be discussed on the canonical public
thread, as opposed to private channels, GitHub pull request reviews or
unrelated venues. This ensures everyone can follow and contribute,
avoids fragmenting the discussion, and makes sure it is fully considered
as part of the PEP review process. Comments, support, concerns and other
feedback on this designated thread are a critical part of what the
Steering Council or PEP-Delegate will consider when reviewing the PEP.

PEP Review & Resolution

Once the authors have completed a PEP, they may request a review for
style and consistency from the PEP editors. However, content review and
acceptance of the PEP is ultimately the responsibility of the Steering
Council, which is formally initiated by opening a Steering Council issue
once the authors (and sponsor, if any) determine the PEP is ready for
final review and resolution.

To expedite the process in selected cases (e.g. when a change is clearly
beneficial and ready to be accepted, but the PEP hasn't been formally
submitted for review yet), the Steering Council may also initiate a PEP
review, first notifying the PEP author(s) and giving them a chance to
make revisions.

The final authority for PEP approval is the Steering Council. However,
whenever a new PEP is put forward, any core developer who believes they
are suitably experienced to make the final decision on that PEP may
offer to serve as its PEP-Delegate by notifying the Steering Council of
their intent. If the Steering Council approves their offer, the
PEP-Delegate will then have the authority to approve or reject that PEP.
For PEPs related to the Python type system, the Typing Council (PEP 729)
provides a recommendation to the Steering Council. To request such a
recommendation, open an issue on the Typing Council issue tracker.

The term "PEP-Delegate" is used under the Steering Council governance
model for the PEP's designated decision maker, who is recorded in the
"PEP-Delegate" field in the PEP's header. The term "BDFL-Delegate" is a
deprecated alias for PEP-Delegate, a legacy of the time when when Python
was led by a BDFL. Any legacy references to "BDFL-Delegate" should be
treated as equivalent to "PEP-Delegate".

An individual offering to nominate themselves as a PEP-Delegate must
notify the relevant authors and (when present) the sponsor for the PEP,
and submit their request to the Steering Council (which can be done via
a new issue ). Those taking on this responsibility are free to seek
additional guidance from the Steering Council at any time, and are also
expected to take the advice and perspectives of other core developers
into account.

The Steering Council will generally approve such self-nominations by
default, but may choose to decline them. Possible reasons for the
Steering Council declining a self-nomination as PEP-Delegate include,
but are not limited to, perceptions of a potential conflict of interest
(e.g. working for the same organisation as the PEP submitter), or simply
considering another potential PEP-Delegate to be more appropriate. If
core developers (or other community members) have concerns regarding the
suitability of a PEP-Delegate for any given PEP, they may ask the
Steering Council to review the delegation.

If no volunteer steps forward, then the Steering Council will approach
core developers (and potentially other Python community members) with
relevant expertise, in an attempt to identify a candidate that is
willing to serve as PEP-Delegate for that PEP. If no suitable candidate
can be found, then the PEP will be marked as Deferred until one is
available.

Previously appointed PEP-Delegates may choose to step down, or be asked
to step down by the Council, in which case a new PEP-Delegate will be
appointed in the same manner as for a new PEP (including deferral of the
PEP if no suitable replacement can be found). In the event that a
PEP-Delegate is asked to step down, this will overrule any prior
acceptance or rejection of the PEP, and it will revert to Draft status.

When such standing delegations are put in place, the Steering Council
will maintain sufficient public records to allow subsequent Councils,
the core developers, and the wider Python community to understand the
delegations that currently exist, why they were put in place, and the
circumstances under which they may no longer be needed.

For a PEP to be accepted it must meet certain minimum criteria. It must
be a clear and complete description of the proposed enhancement. The
enhancement must represent a net improvement. The proposed
implementation, if applicable, must be solid and must not complicate the
interpreter unduly. Finally, a proposed enhancement must be "pythonic"
in order to be accepted by the Steering Council. (However, "pythonic" is
an imprecise term; it may be defined as whatever is acceptable to the
Steering Council. This logic is intentionally circular.) See PEP 2 for
standard library module acceptance criteria.

Except where otherwise approved by the Steering Council, pronouncements
of PEP resolution will be posted to the PEPs category on the Python
Discourse.

Once a PEP has been accepted, the reference implementation must be
completed. When the reference implementation is complete and
incorporated into the main source code repository, the status will be
changed to "Final".

To allow gathering of additional design and interface feedback before
committing to long term stability for a language feature or standard
library API, a PEP may also be marked as "Provisional". This is short
for "Provisionally Accepted", and indicates that the proposal has been
accepted for inclusion in the reference implementation, but additional
user feedback is needed before the full design can be considered
"Final". Unlike regular accepted PEPs, provisionally accepted PEPs may
still be Rejected or Withdrawn even after the related changes have been
included in a Python release.

Wherever possible, it is considered preferable to reduce the scope of a
proposal to avoid the need to rely on the "Provisional" status (e.g. by
deferring some features to later PEPs), as this status can lead to
version compatibility challenges in the wider Python ecosystem. PEP 411
provides additional details on potential use cases for the Provisional
status.

A PEP can also be assigned the status "Deferred". The PEP author or an
editor can assign the PEP this status when no progress is being made on
the PEP. Once a PEP is deferred, a PEP editor can reassign it to draft
status.

A PEP can also be "Rejected". Perhaps after all is said and done it was
not a good idea. It is still important to have a record of this fact.
The "Withdrawn" status is similar - it means that the PEP author
themselves has decided that the PEP is actually a bad idea, or has
accepted that a competing proposal is a better alternative.

When a PEP is Accepted, Rejected or Withdrawn, the PEP should be updated
accordingly. In addition to updating the Status field, at the very least
the Resolution header should be added with a direct link to the relevant
post making a decision on the PEP.

PEPs can also be superseded by a different PEP, rendering the original
obsolete. This is intended for Informational PEPs, where version 2 of an
API can replace version 1.

The possible paths of the status of PEPs are as follows:

[PEP process flow diagram]

While not shown in the diagram, "Accepted" PEPs may technically move to
"Rejected" or "Withdrawn" even after acceptance. This will only occur if
the implementation process reveals fundamental flaws in the design that
were not noticed prior to acceptance of the PEP. Unlike Provisional
PEPs, these transitions are only permitted if the accepted proposal has
not been included in a Python release - released changes must instead go
through the regular deprecation process (which may require a new PEP
providing the rationale for the deprecation).

Some Informational and Process PEPs may also have a status of "Active"
if they are never meant to be completed. E.g. PEP 1 (this PEP).

PEP Maintenance

In general, PEPs are no longer substantially modified after they have
reached the Accepted, Final, Rejected or Superseded state. Once
resolution is reached, a PEP is considered a historical document rather
than a living specification. Formal documentation of the expected
behavior should be maintained elsewhere, such as the Language Reference
for core features, the Library Reference for standard library modules or
the PyPA Specifications for packaging.

If changes based on implementation experience and user feedback are made
to Standards track PEPs while in the Provisional or (with SC approval)
Accepted state, they should be noted in the PEP, such that the PEP
accurately describes the implementation at the point where it is marked
Final.

Active (Informational and Process) PEPs may be updated over time to
reflect changes to development practices and other details. The precise
process followed in these cases will depend on the nature and purpose of
the PEP in question.

Occasionally, a Deferred or even a Withdrawn PEP may be resurrected with
major updates, but it is often better to just propose a new one.

What belongs in a successful PEP?

Each PEP should have the following parts/sections:

1.  Preamble -- 2822 style headers containing meta-data about the PEP,
    including the PEP number, a short descriptive title (limited to a
    maximum of 44 characters), the names, and optionally the contact
    info for each author, etc.

2.  Abstract -- a short (~200 word) description of the technical issue
    being addressed.

3.  Motivation -- The motivation is critical for PEPs that want to
    change the Python language, library, or ecosystem. It should clearly
    explain why the existing language specification is inadequate to
    address the problem that the PEP solves. This can include collecting
    documented support for the PEP from important projects in the Python
    ecosystem. PEP submissions without sufficient motivation may be
    rejected.

4.  Rationale -- The rationale fleshes out the specification by
    describing why particular design decisions were made. It should
    describe alternate designs that were considered and related work,
    e.g. how the feature is supported in other languages.

    The rationale should provide evidence of consensus within the
    community and discuss important objections or concerns raised during
    discussion.

5.  Specification -- The technical specification should describe the
    syntax and semantics of any new language feature. The specification
    should be detailed enough to allow competing, interoperable
    implementations for at least the current major Python platforms
    (CPython, Jython, IronPython, PyPy).

6.  Backwards Compatibility -- All PEPs that introduce backwards
    incompatibilities must include a section describing these
    incompatibilities and their severity. The PEP must explain how the
    author proposes to deal with these incompatibilities. PEP
    submissions without a sufficient backwards compatibility treatise
    may be rejected outright.

7.  Security Implications -- If there are security concerns in relation
    to the PEP, those concerns should be explicitly written out to make
    sure reviewers of the PEP are aware of them.

8.  How to Teach This -- For a PEP that adds new functionality or
    changes language behavior, it is helpful to include a section on how
    to teach users, new and experienced, how to apply the PEP to their
    work.

    This section may include key points and recommended documentation
    changes that would help users adopt a new feature or migrate their
    code to use a language change.

9.  Reference Implementation -- The reference implementation must be
    completed before any PEP is given status "Final", but it need not be
    completed before the PEP is accepted. While there is merit to the
    approach of reaching consensus on the specification and rationale
    before writing code, the principle of "rough consensus and running
    code" is still useful when it comes to resolving many discussions of
    API details.

    The final implementation must include test code and documentation
    appropriate for either the Python language reference or the standard
    library reference.

10. Rejected Ideas -- Throughout the discussion of a PEP, various ideas
    will be proposed which are not accepted. Those rejected ideas should
    be recorded along with the reasoning as to why they were rejected.
    This both helps record the thought process behind the final version
    of the PEP as well as preventing people from bringing up the same
    rejected idea again in subsequent discussions.

    In a way this section can be thought of as a breakout section of the
    Rationale section that is focused specifically on why certain ideas
    were not ultimately pursued.

11. Open Issues -- While a PEP is in draft, ideas can come up which
    warrant further discussion. Those ideas should be recorded so people
    know that they are being thought about but do not have a concrete
    resolution. This helps make sure all issues required for the PEP to
    be ready for consideration are complete and reduces people
    duplicating prior discussion.

12. Footnotes -- A collection of footnotes cited in the PEP, and a place
    to list non-inline hyperlink targets.

13. Copyright/license -- Each new PEP must be placed under a dual
    license of public domain and CC0-1.0-Universal (see this PEP for an
    example).

PEP Formats and Templates

PEPs are UTF-8 encoded text files using the reStructuredText format.
reStructuredText allows for rich markup that is still quite easy to
read, but also results in good-looking and functional HTML. PEP 12
contains instructions and a PEP template <12#suggested-sections>.

The PEP text files are automatically converted to HTML (via a
Sphinx-based build system <676>) for easier online reading.

PEP Header Preamble

Each PEP must begin with an 2822 style header preamble. The headers must
appear in the following order. Headers marked with "*" are optional and
are described below. All other headers are required.

    PEP: <pep number>
    Title: <pep title>
    Author: <list of authors' names and optionally, email addrs>
    * Sponsor: <name of sponsor>
    * PEP-Delegate: <PEP delegate's name>
    Discussions-To: <URL of current canonical discussion thread>
    Status: <Draft | Active | Accepted | Provisional | Deferred | Rejected |
             Withdrawn | Final | Superseded>
    Type: <Standards Track | Informational | Process>
    * Topic: <Governance | Packaging | Release | Typing>
    * Requires: <pep numbers>
    Created: <date created on, in dd-mmm-yyyy format>
    * Python-Version: <version number>
    Post-History: <dates, in dd-mmm-yyyy format,
                   inline-linked to PEP discussion threads>
    * Replaces: <pep number>
    * Superseded-By: <pep number>
    * Resolution: <date in dd-mmm-yyyy format, linked to the acceptance/rejection post>

The Author header lists the names, and optionally the email addresses of
all the authors/owners of the PEP. The format of the Author header
values must be:

    Random J. User <random@example.com>

if the email address is included, and just:

    Random J. User

if the address is not given. Most PEP authors use their real name, but
if you prefer a different name and use it consistently in discussions
related to the PEP, feel free to use it here.

If there are multiple authors, each should be on a separate line
following 2822 continuation line conventions. Note that personal email
addresses in PEPs will be obscured as a defense against spam harvesters.

The Sponsor field records which developer (core, or otherwise approved
by the Steering Council) is sponsoring the PEP. If one of the authors of
the PEP is a core developer then no sponsor is necessary and thus this
field should be left out.

The PEP-Delegate field is used to record the individual appointed by the
Steering Council to make the final decision on whether or not to approve
or reject a PEP.

Note: The Resolution header is required for Standards Track PEPs only.
It contains a URL that should point to an email message or other web
resource where the pronouncement about (i.e. approval or rejection of)
the PEP is made.

The Discussions-To header provides the URL to the current canonical
discussion thread for the PEP. For email lists, this should be a direct
link to the thread in the list's archives, rather than just a mailto: or
hyperlink to the list itself.

The Type header specifies the type of PEP: Standards Track,
Informational, or Process.

The optional Topic header lists the special topic, if any, the PEP
belongs under. See the topic-index for the existing topics.

The Created header records the date that the PEP was assigned a number,
while Post-History is used to record the dates of and corresponding URLs
to the Discussions-To threads for the PEP, with the former as the linked
text, and the latter as the link target. Both sets of dates should be in
dd-mmm-yyyy format, e.g. 14-Aug-2001.

Standards Track PEPs will typically have a Python-Version header which
indicates the version of Python that the feature will be released with.
Standards Track PEPs without a Python-Version header indicate
interoperability standards that will initially be supported through
external libraries and tools, and then potentially supplemented by a
later PEP to add support to the standard library. Informational and
Process PEPs do not need a Python-Version header.

PEPs may have a Requires header, indicating the PEP numbers that this
PEP depends on.

PEPs may also have a Superseded-By header indicating that a PEP has been
rendered obsolete by a later document; the value is the number of the
PEP that replaces the current document. The newer PEP must have a
Replaces header containing the number of the PEP that it rendered
obsolete.

Auxiliary Files

PEPs may include auxiliary files such as diagrams. Such files should be
named pep-XXXX-Y.ext, where "XXXX" is the PEP number, "Y" is a serial
number (starting at 1), and "ext" is replaced by the actual file
extension (e.g. "png").

Alternatively, all support files may be placed in a subdirectory called
pep-XXXX, where "XXXX" is the PEP number. When using a subdirectory,
there are no constraints on the names used in files.

Changing Existing PEPs

Draft PEPs are freely open for discussion and proposed modification, at
the discretion of the authors, until submitted to the Steering Council
or PEP-Delegate for review and resolution. Substantive content changes
should generally be first proposed on the PEP's discussion thread listed
in its Discussions-To header, while copyedits and corrections can be
submitted as a GitHub issue or GitHub pull request. PEP authors with
write access to the PEP repository can update the PEPs themselves by
using git push or a GitHub PR to submit their changes. For guidance on
modifying other PEPs, consult the PEP Maintenance section.

See the Contributing Guide for additional details, and when in doubt,
please check first with the PEP author and/or a PEP editor.

Transferring PEP Ownership

It occasionally becomes necessary to transfer ownership of PEPs to a new
champion. In general, it is preferable to retain the original author as
a co-author of the transferred PEP, but that's really up to the original
author. A good reason to transfer ownership is because the original
author no longer has the time or interest in updating it or following
through with the PEP process, or has fallen off the face of the 'net
(i.e. is unreachable or not responding to email). A bad reason to
transfer ownership is because the author doesn't agree with the
direction of the PEP. One aim of the PEP process is to try to build
consensus around a PEP, but if that's not possible, an author can always
submit a competing PEP.

If you are interested in assuming ownership of a PEP, you can also do
this via pull request. Fork the PEP repository, make your ownership
modification, and submit a pull request. You should mention both the
original author and @python/pep-editors in a comment on the pull
request. (If the original author's GitHub username is unknown, use
email.) If the original author doesn't respond in a timely manner, the
PEP editors will make a unilateral decision (it's not like such
decisions can't be reversed :).

PEP Editor Responsibilities & Workflow

A PEP editor must be added to the @python/pep-editors group on GitHub
and must watch the PEP repository.

Note that developers with write access to the PEP repository may handle
the tasks that would normally be taken care of by the PEP editors.
Alternately, even developers may request assistance from PEP editors by
mentioning @python/pep-editors on GitHub.

For each new PEP that comes in an editor does the following:

-   Make sure that the PEP is either co-authored by a core developer,
    has a core developer as a sponsor, or has a sponsor specifically
    approved for this PEP by the Steering Council.
-   Read the PEP to check if it is ready: sound and complete. The ideas
    must make technical sense, even if they don't seem likely to be
    accepted.
-   The title should accurately describe the content.
-   The file name extension is correct (i.e. .rst).
-   Ensure that everyone listed as a sponsor or co-author of the PEP who
    has write access to the PEP repository is added to
    .github/CODEOWNERS.
-   Skim the PEP for obvious defects in language (spelling, grammar,
    sentence structure, etc.), and code style (examples should conform
    to PEP 7 & PEP 8). Editors may correct problems themselves, but are
    not required to do so (reStructuredText syntax is checked by the
    repo's CI).
-   If a project is portrayed as benefiting from or supporting the PEP,
    make sure there is some direct indication from the project included
    to make the support clear. This is to avoid a PEP accidentally
    portraying a project as supporting a PEP when in fact the support is
    based on conjecture.

If the PEP isn't ready, an editor will send it back to the author for
revision, with specific instructions. If reST formatting is a problem,
ask the author(s) to use PEP 12 as a template and resubmit.

Once the PEP is ready for the repository, a PEP editor will:

-   Check that the author has selected a valid PEP number or assign them
    a number if they have not (almost always just the next available
    number, but sometimes it's a special/joke number, like 666 or 3141).

    Remember that numbers below 100 are meta-PEPs.

-   Check that the author has correctly labeled the PEP's type
    ("Standards Track", "Informational", or "Process"), and marked its
    status as "Draft".

-   Ensure all CI build and lint checks pass without errors, and there
    are no obvious issues in the rendered preview output.

-   Merge the new (or updated) PEP.

-   Inform the author of the next steps (open a discussion thread and
    update the PEP with it, post an announcement, etc).

Updates to existing PEPs should be submitted as a GitHub pull request.

Many PEPs are written and maintained by developers with write access to
the Python codebase. The PEP editors monitor the PEP repository for
changes, and correct any structure, grammar, spelling, or markup
mistakes they see.

PEP editors don't pass judgment on PEPs. They merely do the
administrative & editorial part (which is generally a low volume task).

Resources:

-   Index of Python Enhancement Proposals
-   Following Python's Development
-   Python Developer's Guide

Footnotes

Copyright

This document is placed in the public domain or under the
CC0-1.0-Universal license, whichever is more permissive.