public static Proposition getRuleOfAntecedentFrame(ControlFrame frame) {
    if (frame.state == Logic.KWD_PATTERN) {
      { ControlFrame parent = frame.up;

        if (parent != null) {
          return (((Proposition)(KeyValueList.dynamicSlotValue(parent.dynamicSlots, Logic.SYM_LOGIC_ANTECEDENTS_RULE, null))));
        }
      }
    }
    return (null);
  }