List all stdlib packages

import_cleanup.py

def get_stdlib_names():
    import distutils.sysconfig as sysconfig
    import os
    import sys

    std_lib = sysconfig.get_python_lib(standard_lib=True)
    pathed_dirs = sorted(sys.path[:], key=lambda s: len(s), reverse=True)
    prefixes = filter(lambda path: path.startswith(std_lib), pathed_dirs)

    for top, dirs, files in os.walk(std_lib):
        for maybe_prefix in prefixes:
            if top.startswith(maybe_prefix):
                prefix = top[len(maybe_prefix)+1:]
                break

        for nm in files:
            if prefix[:13] == 'site-packages':
                continue
            if nm[-3:] == '.so' and top[-11:] == 'lib-dynload':
                yield nm[0:-3]
            elif nm == '__init__.py':
                yield top[len(std_lib)+1:].replace(os.path.sep,'.')              
            elif nm[-3:] == '.py':
                yield os.path.join(prefix, nm)[:-3].replace(os.path.sep,'.')

    for builtin in sys.builtin_module_names:
        yield builtin