src/transformers/models/ctrl/modeling_tf_ctrl.py/TFCTRLMainLayer/_prune_heads
class TFCTRLMainLayer:    def _prune_heads(self, heads_to_prune):
        """
        Prunes heads of the model. heads_to_prune: dict of {layer_num: list of heads to prune in this layer}
        """
        raise NotImplementedError