Double Then Quadruple

The function double(n: int) -> int is finished. Complete quadruple(n: int) -> int so it returns four times the number by calling double twice, once on the number and once on that result, rather than multiplying by 4 yourself. Do NOT write a main block or any top-level test code; the tests construct the calls. Input: one line, an integer, which the tests read and pass to quadruple before printing the value it returns.