def scheduler(epoch):
    """Learning Rate Schedule

    Learning rate is scheduled to be reduced after 51, 101, 201 epochs.
    Called automatically every epoch as part of callbacks during training.

    # Arguments
        epoch (int): The number of epochs

    # Returns
        learning rate(float32)
    """
    if epoch < 51:
        return 0.1
    if epoch < 101:
        return 0.01
    if epoch < 201:
        return 0.001
    return 0.0001