def get(self):
        # Get collection_id from parser
        args = collection_get_book_parser.parse_args()
        collection_id = args.get('collection_id')

        # Is collection exist
        if not Collection.is_collection_exists_by_id(collection_id):
            return {'message': 'Resource not found'}, 404
        collection = Collection(collection_id)
        books = collection.get_book_in_collection()
        return {'books': books}, 200
    def get(self):
        # Get collection_id and book_id from parser
        token = request.headers.get('AUTH-TOKEN')
        token_info = jwt.decode(token, SECRET_KEY, algorithms='HS256')
        user_id = token_info['id']

        # Get info from parser
        args = collection_copy_parser.parse_args()
        collection_id = args.get('collection_id')
        new_collection_name = args.get('new_collection_name')

        # Target collection existed check
        if not Collection.is_collection_exists_by_id(collection_id):
            return {'message': 'Resource not found'}, 404
        if Collection.is_collection_exists_by_both_id(user_id, collection_id):
            return {'message': 'You cannot copy your own collection'}, 201
        collection = Collection(collection_id)
        collection_name = collection.get_collection_name()

        # Target collection has same name with certain collection owned by user
        if (Collection.is_collection_exists_by_name(
                user_id, collection_name)) and (new_collection_name is None):
            return {
                'message': 'You already has a collection with same name.'
            }, 201
        if not new_collection_name is None:
            if Collection.is_collection_exists_by_name(user_id,
                                                       new_collection_name):
                return {
                    'message': 'You already has a collection with same name'
                }, 201
        else:
            new_collection_name = collection_name
        Collection.post_new_collection(user_id, new_collection_name)
        Collection.copy_collection(
            collection_id,
            Collection.get_collection_id_by_name(user_id, new_collection_name))
        return {'message': 'Copy collection successfully'}, 200