getTianShen method Null safety

String getTianShen()

Implementation

String getTianShen() {
  String dayZhi = _lunar!.getDayZhiExact();
  int offset = LunarUtil.ZHI_TIAN_SHEN_OFFSET[dayZhi]!;
  return LunarUtil.TIAN_SHEN[(_zhiIndex + offset) % 12 + 1];
}