Using a function rand5() that returns an integer from 1 to 5 (inclusive) with uniform probability, implement a function rand7() that returns an integer from 1 to 7 (inclusive).

Example:

>>> from random import randint
>>> rand5 = lambda: randint(0, 4)
>>> rand7 = coding_problem_45(rand5)
>>> 0 <= rand7 < 7
True