def _call(self, x):
        """Return ``self(x)``."""

        # Convert to array with most
        arr = self._asarray(x)
        svd_diag = np.linalg.svd(arr, compute_uv=False)

        # Rotate the axes so the svd-direction is first
        s_reordered = moveaxis(svd_diag, -1, 0)

        # Return nuclear norm
        return self.outernorm(self.pwisenorm(s_reordered))
Return ``self(x)``.