Returns a concatenation of two sequences.

A + B

A

Any sequence.

B

Sequence of the same type as A.

the same as used as sequence operands

O(k)

>>> "AB" + "CD"
'ABCD'
>>> [0, 1] + [2, 3]
[0, 1, 2, 3]
>>> (0, 1) + (2, 3)
(0, 1, 2, 3)

#TODO