'Store a key-value pair into the sessions data associated with this
request. This data is stored server-side and cannot be modified by
the client.
Args:
session_id (string): The ID of this session as returned from check_auth
key (string): The key to store the data under
value (any): The data to store'

def set_session_data(self, session_id, key, value):

    sess = self._get_session_info(session_id)
    sess.setdefault('serverdict', {})[key] = value
    self._save_session(sess)
