def train_step_code():
    with tf.GradientTape() as tape:
        loss = loss_function()
    grads = tape.gradient(loss, vars)
    opt.apply_gradients(zip(grads, vars))
    return loss
def train_step_code():
    with tf.GradientTape() as tape:
        loss = loss_function()
    grads = tape.gradient(loss, vars)
    opt.apply_gradients(zip(grads, vars))
    return loss