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PEP: 2
Title: Procedure for Adding New Modules
Version: 26c61cd277ed
Last-Modified:  2012-05-30 20:43:49 +1000 (Wed, 30 May 2012)
Author: Martijn Faassen <faassen at>
Status: Final
Type: Process
Created: 07-Jul-2001
Post-History: 07-Jul-2001, 09-Mar-2002

PEP Replacement

    This PEP has been superseded by the updated material in the Python
    Developer's Guide [1].


    The Python Standard Library contributes significantly to Python's
    success.  The language comes with "batteries included", so it is
    easy for people to become productive with just the standard
    library alone.  It is therefore important that this library grows
    with the language, and that such growth is supported and

    Many contributions to the library are not created by core
    developers but by people from the Python community who are experts
    in their particular field.  Furthermore, community members are
    also the users of the standard library, applying it in a great
    diversity of settings.  This makes the community well equipped to
    detect and report gaps in the library; things that are missing but
    should be added.

    New functionality is commonly added to the library in the form of
    new modules.  This PEP will describe the procedure for the
    _addition_ of new modules.  PEP 4 deals with procedures for
    deprecation of modules; the _removal_ of old and unused modules
    from the standard library.  Finally there is also the issue of
    _changing_ existing modules to make the picture of library
    evolution complete.  PEP 3 and PEP 5 give some guidelines on this.
    The continued maintenance of existing modules is an integral part
    of the decision on whether to add a new module to the standard
    library.  Therefore, this PEP also introduces concepts
    (integrators, maintainers) relevant to the maintenance issue.


    The integrators are a group of people with the following

    - They determine if a proposed contribution should become part of
      the standard library.

    - They integrate accepted contributions into the standard library.

    - They produce standard library releases.

   This group of people shall be PythonLabs, led by Guido.


    All contributions to the standard library need one or more
    maintainers.  This can be an individual, but it is frequently a
    group of people such as the XML-SIG.  Groups may subdivide
    maintenance tasks among themselves.  One ore more maintainers
    shall be the _head maintainer_ (usually this is also the main
    developer).  Head maintainers are convenient people the
    integrators can address if they want to resolve specific issues,
    such as the ones detailed later in this document.


    Contributions to the standard library have been developed by one
    or more developers.  The initial maintainers are the original
    developers unless there are special circumstances (which should be
    detailed in the PEP proposing the contribution).

Acceptance Procedure

    When developers wish to have a contribution accepted into the
    standard library, they will first form a group of maintainers
    (normally initially consisting of themselves).

    Then, this group shall produce a PEP called a library PEP. A
    library PEP is a special form of standards track PEP.  The library
    PEP gives an overview of the proposed contribution, along with the
    proposed contribution as the reference implementation.  This PEP
    should also contain a motivation on why this contribution should
    be part of the standard library.

    One or more maintainers shall step forward as PEP champion (the
    people listed in the Author field are the champions).  The PEP
    champion(s) shall be the initial head maintainer(s).
    As described in PEP 1, a standards track PEP should consist of a
    design document and a reference implementation.  The library PEP
    differs from a normal standard track PEP in that the reference
    implementation should in this case always already have been
    written before the PEP is to be reviewed for inclusion by the
    integrators and to be commented upon by the community; the
    reference implementation _is_ the proposed contribution.

    This different requirement exists for the following reasons:

    - The integrators can only properly evaluate a contribution to the
      standard library when there is source code and documentation to
      look at; i.e. the reference implementation is always necessary
      to aid people in studying the PEP.

    - Even rejected contributions will be useful outside the standard
      library, so there will a lower risk of waste of effort by the
    - It will impress the integrators of the seriousness of
      contribution and will help guard them against having to evaluate
      too many frivolous proposals.

    Once the library PEP has been submitted for review, the
    integrators will then evaluate it.  The PEP will follow the normal
    PEP work flow as described in PEP 1.  If the PEP is accepted, they
    will work through the head maintainers to make the contribution
    ready for integration.

Maintenance Procedure

    After a contribution has been accepted, the job is not over for
    both integrators and maintainers.  The integrators will forward
    any bug reports in the standard library to the appropriate head

    Before the feature freeze preparing for a release of the standard
    library, the integrators will check with the head maintainers for
    all contributions, to see if there are any updates to be included
    in the next release.  The integrators will evaluate any such
    updates for issues like backwards compatibility and may require
    PEPs if the changes are deemed to be large.

    The head maintainers should take an active role in keeping up to
    date with the Python development process.  If a head maintainer is
    unable to function in this way, he or she should announce the
    intention to step down to the integrators and the rest of the
    maintainers, so that a replacement can step forward.  The
    integrators should at all times be capable of reaching the head
    maintainers by email.

    In the case where no head maintainer can be found (possibly
    because there are no maintainers left), the integrators will issue
    a call to the community at large asking for new maintainers to
    step forward.  If no one does, the integrators can decide to
    declare the contribution deprecated as described in PEP 4.

Open issues

    There needs to be some procedure so that the integrators can
    always reach the maintainers (or at least the head maintainers).
    This could be accomplished by a mailing list to which all head
    maintainers should be subscribed (this could be python-dev).
    Another possibility, which may be useful in any case, is the
    maintenance of a list similar to that of the list of PEPs which
    lists all the contributions and their head maintainers with
    contact info.  This could in fact be part of the list of the PEPs,
    as a new contribution requires a PEP.  But since the
    authors/owners of a PEP introducing a new module may eventually be
    different from those who maintain it, this wouldn't resolve all
    issues yet.

    Should there be a list of what criteria integrators use for
    evaluating contributions?  (Source code but also things like
    documentation and a test suite, as well as such vague things like
    'dependability of the maintainers'.)
    This relates to all the technical issues; check-in privileges,
    coding style requirements, documentation requirements, test suite
    requirements.  These are preferably part of another PEP.

    Should the current standard library be subdivided among
    maintainers?  Many parts already have (informal) maintainers; it
    may be good to make this more explicit.

    Perhaps there is a better word for 'contribution'; the word
    'contribution' may not imply enough that the process (of
    development and maintenance) does not stop after the contribution
    is accepted and integrated into the library.

    Relationship to the mythical Catalog?


    [1] Adding to the Stdlib


    This document has been placed in the public domain.