returnsString()
Saturday, 05 Sep 2026
string(21) "Saturday, 05 Sep 2026"

convertsToString()
string(1) "9"

makesDateTime()
object(DateTime)#2 (3) {
  ["date"]=>
  string(26) "2015-11-21 10:10:39.843214"
  ["timezone_type"]=>
  int(3)
  ["timezone"]=>
  string(14) "Asia/Chongqing"
}

wrongDateTime()
Return value of wrongDateTime() must be an instance of DateTime, string returned