o = mono

    def forward(self, spec: Tensor) -&gt; Tensor:
        &#34;&#34;&#34;
        Args:
            spec: complex_tensor (Tensor): Tensor shape of
                `(..., complex=2)`

        Returns:
            Tensor: Power/Mag of input
                `(...,)`
        &#34;&#34;&#34;
        # take the magnitude
        spec = torchaudio.functional.complex_norm(spec, power=self.power)

        # downmix in the mag domain to preserve energy
        if self.mono:
            spec = torch.mean(spe