input: def understand_recursion(number: int) -> int:
      """ This function is to understand recursion in Python.
      It defines a recursive function to calculate the factorial of a given number.
      >>> understand_recursion(5)
      120
      >>> understand_recursion(3)
      6
      """
      def factorial(n):
          if n == 1:
              return 1
          else:
              return n * factorial(n - 1)
      
      return factorial(number)
output:     def factorial(n):
          if n == 1:
              return 1
          else:
              return n * factorial(n - 1)
      
      return factorial(number)