label([7]) = a1:[7]

label([[7]]) = a1:[a2:[7]]

label([[70],[80,90]]) = a1:[a2:[70],a3:[80,90]]

label(b) = a1:[a2:[],a2]

label(c) = a1:[a2:[a3:[],a3],a2]

label([a,b,c]) = a1:[a2:[],a3:[a2,a2],a4:[a3,a3]]

label(a) = a1:[1,2,3,a2:[a3:[a4:[a1,a5:[a1]]]],a1]

label([a,b]) = a1:[a2:[1,2,3,a3:["abc",a2,a2,a2],a3,a3],a3]

label([10,20,30]) = a1:[10,20,30]

label(a2) = a1:[]

label(a4) = a1:[a2:[a3:[a4:[],a5:[],a4]],a6:[a2,a7:[a2]],a1]

label(a4) = a1:[10,"twenty",a1,a1]