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 :obj`EfficientFormerClsHead`, we just
        obtain the feature of the last stage.
        """
        # The EfficientFormerClsHead 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 :obj`EfficientFormerClsHead`, we just
        obtain the feature of the last stage.
        
mmpretrain/models/heads/efficientformer_head.py