code: def fixed_values(self):
          
          values = []
          values.extend([ prefix_factor(param) * param['value'] for param in self.fixed_parameters ])
          values.extend([ prefix_factor(const) * get_constant(const['value']) for const in self.constants ])
  
          return tuple(values)
docs: A flat tuple of all values corresponding to `scipy_data_fitting.Fit.fixed_parameters`
          and `scipy_data_fitting.Fit.constants` after applying any prefixes.
  
          The values mimic the order of those lists.