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Factorial
In mathematics, the factorial of a non-negative integer n,
denoted by n!, is the product of all positive integers less
than or equal to n. For example: 5! = 5 * 4 * 3 * 2 * 1 = 120.
By convention the value of 0! is 1.
Write a function to calculate factorial for a given input. If input
is below 0 or above 12 throw an exception of type ValueError (Python).