"isNil" "test if self is nil" perform: method with: x with: y with: z with: a with: b with: c | a b c d e f g | " a := 'this is ''good'. a := #xxx niceMethod. " b := -30 xxx nil this. instanceClass := 10. (jjj xxx: 10 xy) zzz: (10 fuck: 20 you: 40) yyy: kkk. [ spec plus: 20]