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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def book(self, name):
 """Return an API wrapper for the given order book. :param name: Order book name (e.g. "btc_cad"). :type name: str | unicode :return: Order book API wrapper. :rtype: quadriga.book.OrderBook :raise InvalidOrderBookError: If an invalid order book is given. **Example**: .. doctest:: """

        self._validate_order_book(name)
        return OrderBook(name, self._rest_client, self._logger)