def get_next_id(self):
        try:
            query = {'_id': 'last_id'}
            update = {'$inc': {'id': 1}}
            fn = self.db.internal.find_and_modify
            row = fn(query, update, upsert=True, new=True)
        except Exception as e:
            raise DatabaseException(e)
        return row['id']
def step_impl(context):
    data = json.loads(context.text)
    receiver_name = re.match(r"\<(\w+)'s id\>", data['receiver']).group(1)
    data['receiver'] = context.users[receiver_name]['id']
    context.request.add_data(data)