input: Write a python function to calculate the factorial of the larger of two given numbers.
  assert factorial_of_larger(5, 3) == 120
  assert factorial_of_larger(4, 6) == 720
  assert factorial_of_larger(7, 7) == 5040
output: def factorial_of_larger(a, b):
      def factorial(n):
          if n == 0 or n == 1:
              return 1
          else:
              return n * factorial(n-1)
      
      larger = max(a, b)
      return factorial(larger)