def pre_logits(self, feats: Tuple[torch.Tensor]) -> torch.Tensor:
        """The process before the final classification head.

        The input ``feats`` is a tuple of tensor, and each tensor is the
        feature of a backbone stage. In ``MultiLabelClsHead``, we just obtain
        the feature of the last stage.
        """
        # The MultiLabelClsHead doesn't have other module, just return after
        # unpacking.
        return feats[-1]
The process before the final classification head.

        The input ``feats`` is a tuple of tensor, and each tensor is the
        feature of a backbone stage. In ``MultiLabelClsHead``, we just obtain
        the feature of the last stage.
        
mmpretrain/models/heads/multi_label_cls_head.py