shift demo importers to importers.py (destined for Demo/ ?) switch to isinstance() rather than direct type comparisons removing chaining concept update ImportManager.install() to take an optional namespace to install   itself in. this will be useful for setting up rexec environments. minor comment nits
shift demo importers to importers.py (destined for Demo/ ?)
switch to isinstance() rather than direct type comparisons
removing chaining concept
update ImportManager.install() to take an optional namespace to install
  itself in. this will be useful for setting up rexec environments.
minor comment nits

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator