def forecast_lstm(model, batch_size, X):
    """
    make a one-step forecast
    :param model: the model
    :param batch_size: the batch size
    :param X: the X to generate predictions from
    :return: the predicted Y
    """
    X = X.reshape(1, 1, len(X))
    yhat = model.predict(X, batch_size=batch_size)
    return yhat[0, 0]