':param db_name: database name (be careful with production databases)
:param collection_name: collection name (default: mongo_dict_data)
:param connection: ``pymongo.Connection`` instance. If it\'s ``None``
(default) new connection with default options will
be created'

def __init__(self, db_name, collection_name='mongo_dict_data', connection=None):

    if (connection is not None):
        self.connection = connection
    else:
        self.connection = Connection()
    self.db = self.connection[db_name]
    self.collection = self.db[collection_name]
