delphi – InheritsFrom和is运算符之间有什么区别？

type
  TMyClass = class(TObject);
  TMyChildClass = class(TMyClass);

var
  MyObj : TMyChildClass;

procedure TForm1.Test();
var
  ResultA : Boolean;
  ResultB : Boolean;
begin
  //Using TObject.InheritsFrom
  ResultA := MyObj.InheritsFrom(TMyClass);

  //Using 'is' operator
  ResultB := MyObj is TMyClass;

  //Showing results
  Showmessage(
    'InheritsFrom = ' + BoolToStr(ResultA,TruE) + sLineBreak +
    'is = ' + BoolToStr(ResultB,TruE)
  );
end;

使用is运算符而不是TObject.InheritsFrom函数有什么不同吗？