code: def npar_adj(self):
          
          pass
          np = 0
          for t in self.parameter_data.partrans:
              if t not in ["fixed", "tied"]:
                  np += 1
          return np
docs: get the number of adjustable parameters (not fixed or tied)
  
          Returns
          -------
          npar_adj : int
              the number of adjustable parameters