def get_layer_groups(self):
        """ Return layers grouped """
        return [
            [self.policy_backbone, self.action_head],
            [self.value_backbone, [y for (x, y) in self.critic_head.named_parameters() if x.endswith('bias')]],
            # OpenAI regularizes only weight on the last layer. I'm just replicating that
            [[y for (x, y) in self.critic_head.named_parameters() if x.endswith('weight')]]
        ]