we are talking about Lists, not arrays from an unrelated library which has to be installed first. what you've done there is simply dishonest In [1]: a = [1,2]

we are talking about Lists, not arrays from an unrelated library which has to be installed first. what you've done there is simply dishonest In [1]: a = [1,2] In [2]: b = [4,5] In [3]: print(a+b) Out [1, 2, 4, 5]