returnsString() Tuesday, 03 Nov 2026 string(20) "Tuesday, 03 Nov 2026" convertsToString() string(1) "9" makesDateTime() object(DateTime)#2 (3) { ["date"]=> string(26) "2015-11-21 08:47:35.536218" ["timezone_type"]=> int(3) ["timezone"]=> string(14) "Asia/Chongqing" } wrongDateTime() Return value of wrongDateTime() must be an instance of DateTime, string returned