'Initializer for _VersionedLibrary.
Args:
name: The name of the library e.g. "django".
url: The URL for the library\'s project page e.g.
"http://www.djangoproject.com/".
description: A short description of the library e.g. "A framework...".
supported_versions: A list of supported version names ordered by release
date e.g. ["v1", "v2", "v3"].
latest_version: The version of the library that will be used when
customers specify "latest." The rule of thumb is that this should
be the newest version that is neither deprecated nor experimental
(although may be experimental if all supported versions are either
deprecated or experimental).
default_version: The version of the library that is enabled by default
in the Python 2.7 runtime or None if the library is not available by
default e.g. "v1".
deprecated_versions: A list of the versions of the library that have been
deprecated e.g. ["v1", "v2"].
experimental_versions: A list of the versions of the library that are
current experimental e.g. ["v1"].'

def __init__(self, name, url, description, supported_versions, latest_version, default_version=None, deprecated_versions=None, experimental_versions=None):

    self.name = name
    self.url = url
    self.description = description
    self.supported_versions = supported_versions
    self.latest_version = latest_version
    self.default_version = default_version
    self.deprecated_versions = (deprecated_versions or [])
    self.experimental_versions = (experimental_versions or [])
