code: def adj_par_names(self):
          
          adj_names = []
          for t,n in zip(self.parameter_data.partrans,
                         self.parameter_data.parnme):
              if t.lower() not in ["tied","fixed"]:
                  adj_names.append(n)
          return adj_names
docs: get the adjustable (not fixed or tied) parameter names
  
          Returns
          -------
          adj_par_names : list
              list of adjustable (not fixed or tied) parameter names