def evaluate_using_acc(model, X_test, y_test, batch_size):
    """ Evaluation function using accuracy.

    # Arguments:
        model: Model to be evaluated.
        X_test: Inputs of the testing set.
        y_test: Outputs of the testing set.
        batch_size: Batch size.

    # Returns:
        Accuracy of the given model.
    """
    _, acc = model.evaluate(X_test, y_test, batch_size=batch_size, verbose=0)
    return acc
