docs: def response(self, parameters):
          r"""Return the forward response in base dimensions
          :math:`\hat{\sigma }(\omega ) = \sigma _\infty \left(1 - \sum_i \frac
          {m_i}{1 + (j \omega \tau_i)^c_i}\right)`
  
          Parameters
          ----------
          pars:
  
          Returns
          -------
          response: Nx2 array, first axis denotes frequencies, seconds real and
                    imaginary parts
          """
          # get a config object
          self._set_parameters(parameters)
          terms = self.m / (1 + (1j * self.w * self.tau) ** self.c)
          # sum up terms
          specs = np.sum(terms, axis=1)
          ccomplex = self.sigmai * (1 - specs)
  
          response = sip_response.sip_response(self.f, ccomplex=ccomplex)
  
          return response