__init__.py 文件源码

def open_resource(name):
    """Open a resource from the zoneinfo subdir for reading.

    Uses the pkg_resources module if available and no standard file
    found at the calculated location.
    """
    name_parts = name.lstrip('/').split('/')
    for part in name_parts:
        if part == os.path.pardir or os.path.sep in part:
            raise ValueError('Bad path segment: %r' % part)
    filename = os.path.join(os.path.dirname(__file__),
                            'zoneinfo', *name_parts)
    if not os.path.exists(filename):
        # http://bugs.launchpad.net/bugs/383171 - we avoid using this
        # unless absolutely necessary to help when a broken version of
        # pkg_resources is installed.
        try:
            from pkg_resources import resource_stream
        except ImportError:
            resource_stream = None

        if resource_stream is not None:
            return resource_stream(__name__, 'zoneinfo/' + name)
    return open(filename, 'rb')