Return the user session for a client.

        :param sid: The session id of the client.
        :param namespace: The Socket.IO namespace. If this argument is omitted
                          the default namespace is used.

        The return value is a dictionary. Modifications made to this
        dictionary are not guaranteed to be preserved unless
        ``save_session()`` is called, or when the ``session`` context manager
        is used.

def get_session(self, sid, namespace=None):
        """Return the user session for a client.

        :param sid: The session id of the client.
        :param namespace: The Socket.IO namespace. If this argument is omitted
                          the default namespace is used.

        The return value is a dictionary. Modifications made to this
        dictionary are not guaranteed to be preserved unless
        ``save_session()`` is called, or when the ``session`` context manager
        is used.
        """
        namespace = namespace or '/'
        eio_session = self.eio.get_session(sid)
        return eio_session.setdefault(namespace, {})