Add handles to all non-container layers in the model.
        Recursively for non-container layers

def add_handles(self, model, forward_handle, backward_handle):
        """
        Add handles to all non-container layers in the model.
        Recursively for non-container layers
        """
        handles_list = []
        for child in model.children():
            if 'nn.modules.container' in str(type(child)):
                handles_list.extend(self.add_handles(child, forward_handle, backward_handle))
            else:
                handles_list.append(child.register_forward_hook(forward_handle))
                handles_list.append(child.register_backward_hook(backward_handle))
        return handles_list