Deletes a list of message handler requests from the database.

def DeleteMessageHandlerRequests(self, requests, cursor=None):
    """Deletes a list of message handler requests from the database."""

    query = "DELETE FROM message_handler_requests WHERE request_id IN ({})"
    request_ids = set([r.request_id for r in requests])
    query = query.format(",".join(["%s"] * len(request_ids)))
    cursor.execute(query, request_ids)