code: def non_fluents(self) -> Dict[str, PVariable]:
          '''Returns non-fluent pvariables.'''
          return { str(pvar): pvar for pvar in self.pvariables if pvar.is_non_fluent() f non_fluents(self) -> Dict[str, PVariable]:
          '''Returns non-fluent pvariables.'''
          return { str(pvar): pvar for pvar in self.pvariables if pvar.is_non_fluent() }
docs: Returns non-fluent pvariables.