src/transformers/models/squeezebert/modeling_squeezebert.py/SqueezeBertSelfAttention/transpose_output
class SqueezeBertSelfAttention:    def transpose_output(self, x):
        """
        - input: [N, C1, W, C2]
        - output: [N, C, W]
        """
        x = x.permute(0, 1, 3, 2).contiguous()  # [N, C1, C2, W]
        new_x_shape = (x.size()[0], self.all_head_size, x.size()[3])  # [N, C, W]
        x = x.view(*new_x_shape)
        return x