code: def parameters(self):
          
  
          try:
              return self._parameters
  
          except AttributeError:
              None
  
          parameters = []
          parameters.extend(self.grid_points.dtype.names)
  
          model_configuration = self._configuration.get("model", {})
  
          # Continuum
          # Note: continuum cannot just be 'True', it should be a dictionary
          n = len(parameters)
          continuum_config = model_configuration.get("continuum", False)
          if continuum_config is not False:
              if not isinstance(continuum_config, dict):
                  raise TypeError("incorrect continuum type")
              for name in set(self.channel_names).intersection(continuum_config):
                  degree = continuum_config[name]
                  if degree is False:
                      continue
  
                  # Note: N_coefficients = degree + 1
                  # Example: degree = 3: a^3 + b^2 + c^1 + d 
                  parameters.extend(["continuum_{0}_{1}".format(name, n) \
                      for n in range(degree + 1)])
  
          # Redshift
          parameters.extend(channel_parameters("z", self.channel_names,
              model_configuration.get("redshift", False)))
  
          # Spectral resolution
          resolution_parameters = channel_parameters(
              "resolution", self.channel_names,
              model_configuration.get("spectral_resolution", False))
          parameters.extend(resolution_parameters)
  
          # Underestimated variance
          parameters.extend(channel_parameters(
              "ln_f", self.channel_names,
              model_configuration.get("underestimated_variance", False)))
  
          # Outlier pixels
          if model_configuration.get("outlier_pixels", False):
              parameters.extend(["Po", "Vo"])
  
          assert len(parameters) == len(set(parameters)), "Duplicate parameters!"
  
          self._resolution_parameters = resolution_parameters
          self._parameters = tuple(parameters)
  
          return self._parameters
docs: Return the model parameters.