Callback, self).__init__()

        self.base_lr = base_lr
        self.max_lr = max_lr
        self.step_size = step_size
        self.mode = mode
        self.gamma = gamma
        if scale_fn == None:
            if self.mode == &#34;triangular&#34;:
                self.scale_fn = lambda x: 1.0
                self.scale_mode = &#34;cycle&#34;
            elif self.mode == &#34;triangular2&#34;:
                self.scale_fn = lambda x: 1 / (2.0 ** (x - 1))
                self.scale_mode = &#34;cycle&#