def InvalidParsedHotlistRefsEmails(full_refs, user_hotlist_emails_to_owners):
  """Find and return invalid e-mails in hotlist full refs.

  Args:
    full_refs: a list of ParsedHotlistRef object specifying both
      user_email and hotlist_name
    user_hotlist_emails_to_owners: a dictionary having for its keys only
      the e-mails of the owners of the hotlists the user had edit permission
      over. (Could also be a set containing these e-mails.)

  Returns:
    A list of invalid e-mails; if none are found, the empty list.
  """
  parsed_emails = [pref.user_email for pref in full_refs]
  invalid_emails = list()
  for email in parsed_emails:
    if email not in user_hotlist_emails_to_owners:
      invalid_emails.append(email)
  return invalid_emails