def METHOD_NAME(self, epoch):
    old_lr = tf.keras.backend.get_value(self.model.optimizer.lr)
    new_lr = self.initial_lr * self.multiplier(epoch)
    tf.keras.backend.set_value(self.model.optimizer.lr, new_lr)
    if hasattr(self.model.optimizer, "momentum") and self.momentum_correction:
        # See the paper cited above for more information about momentum correction.
        self.restore_momentum = tf.keras.backend.get_value(
            self.model.optimizer.momentum
        )
        tf.keras.backend.set_value(
            self.model.optimizer.momentum, self.restore_momentum * new_lr / old_lr
        )