Vel factory function

def create(model_config, epochs, optimizer, model, source, storage, scheduler=None, callbacks=None, max_grad_norm=None):
    """ Vel factory function """
    return SimpleTrainCommand(
        epochs=epochs,
        model_config=model_config,
        model_factory=model,
        optimizer_factory=optimizer,
        scheduler_factory=scheduler,
        source=source,
        storage=storage,
        callbacks=callbacks,
        max_grad_norm=max_grad_norm
    )