input: Write a python function to compute the factorial of a given non-negative integer.
  assert Factorial.compute_factorial(5) == 120
  assert Factorial.compute_factorial(0) == 1
  assert Factorial.compute_factorial(3) == 6
  assert Factorial.compute_factorial(-1) == None
output: class Factorial:
      @staticmethod
      def compute_factorial(n):
          if n < 0:
              return None
          if n == 0:
              return 1
          factorial = 1
          for i in range(1, n + 1):
              factorial *= i
          return factorial