def METHOD_NAME(self, subject_id, entity_id, info, timestamp=0):
    """Stores session information in the cache. Assumes that the subject_id
    is unique within the context of the Service Provider.
    :param subject_id: The subject identifier
    :param entity_id: The identifier of the entity_id/receiver of an
        assertion
    :param info: The session info, the assertion is part of this
    :param timestamp: A time after which the assertion is not valid.
    """
    if isinstance(timestamp, datetime) or isinstance(timestamp, time.struct_time):
        timestamp = time.strftime(TIME_FORMAT, timestamp)
    doc = {
        "subject_id": subject_id,
        "entity_id": entity_id,
        "info": info,
        "timestamp": timestamp,
    }
    _ = self._cache.insert_one(doc)