docs: def set_area_to_sip_signature(self, xmin, xmax, zmin, zmax, spectrum):
          """Parameterize the eit instance by supplying one
          SIP spectrum and the area to apply to.
  
          Parameters
          ----------
          xmin : float
              Minimum x coordinate of the area
          xmax : float
              Maximum x coordinate of the area
          zmin : float
              Minimum z coordinate of the area
          zmax : float
              Maximum z coordinate of the area
          spectrum : sip_response
              SIP spectrum to use for parameterization
  
          """
          assert isinstance(spectrum, (sip_response, sip_response2))
          assert np.all(self.frequencies == spectrum.frequencies)
          for frequency, rmag, rpha in zip(
                  self.frequencies, spectrum.rmag, spectrum.rpha):
              td = self.tds[frequency]
              pidm, pidp = td.a['forward_model']
              td.parman.modify_area(pidm, xmin, xmax, zmin, zmax, rmag)
              td.parman.modify_area(pidp, xmin, xmax, zmin, zmax, rpha)