def __init__(self, url=None):
"""Create a new client instance.
The url argument can be a TransmissionURL object or dict with any
combination of the following keys:
host, port, path, username, password, ssl
"""
if url is None:
url = TransmissionURL()
Transmission.__init__(self, **url)
self._cache = {}
self._cache["session"] = TransmissionRPC("session", setter=self.session)
self._cache["torrents"] = {}
