code: def add_homogeneous_model(self, magnitude, phase=0):
          
          if self.assignments['forward_model'] is not None:
              print('model already set, will overwrite')
  
          # generate distributions
          magnitude_model = np.ones(self.grid.nr_of_elements) * magnitude
          phase_model = np.ones(self.grid.nr_of_elements) * phase
          pid_mag = self.parman.add_data(magnitude_model)
          pid_pha = self.parman.add_data(phase_model)
  
          self.assignments['forward_model'] = [pid_mag, pid_pha]
          return pid_mag, pid_pha
docs: Add a homogeneous resistivity model to the tomodir. This is useful
          for synthetic measurements.
  
          Parameters
          ----------
          magnitude : float
              magnitude [Ohm m] value of the homogeneous model
          phase : float, optional
              phase [mrad] value of the homogeneous model
  
  
          Returns
          -------
          pid_mag : int
              ID value of the parameter set of the magnitude model
          pid_pha : int
              ID value of the parameter set of the phase model
  
          Note that the parameter sets are automatically registered as the
          forward models for magnitude and phase values.