Moved to XHTML 1.0 transitional, employing the appropriate filename extension
and anchor identifier structure.
Adjusted the pop-up element positioning.
1classA: 2"A class with attribute and method." 3x=123 4defm(self,x): 5self.x=x 6defn(self,y=x): 7self.y=y 8 9a1=A() 10a2=A() 11y=A.x 12a1.m(321) 13a2.m("321") 14z1=a1.x 15z2=a2.x 16a1.n(123) 17a2.n("123") 18a2.n()