t = O (_t1::a)
()
t = O ((_t2::a1) : (_t3::[a1]))
()
t = O ((_t4::a2) : (_t5::a2) : (_t6::[a2]))
()
t = O ((_t7::Maybe [Integer]) : Just [2,2] :
       (_t8::[Maybe [Integer]]))
()
t = O (Just [1,1] : Just [2,2] : (_t9::[Maybe [Integer]]))