    def forward_features(self, x):
        """forward feature function"""

        # x"s shape : [B, C, H, W]

        x = self.stem(x)  # Shape : [B, C, H/4, W/4]

        for idx in range(self.num_stages):
            att_inputs = self.patch_embed_stages[idx](x)
            x = self.mhca_stages[idx](att_inputs)

        return x
forward feature function
towhee/models/mpvit/mpvit.py