code: def get_input_var_names(self):
          
          in_vars = copy.copy(self.input_vars)
          for idx, var in enumerate(in_vars):
              if self._map_in_out(var) is not None:
                  in_vars[idx] = self._map_in_out(var)
          return in_vars
docs: Return a list of variables names that can be set as input.
  
          Returns
          -------
          var_names : list[str]
              A list of variable names that can be set from the outside