input: Write a function to understand the concept of recursion in Python by defining a recursive function to calculate the factorial of a number. If the given number is 1, return 1. Otherwise, return the product of the number and the factorial of the number minus one. Finally, calculate the factorial of number 5 and print the result.
  
  def factorial(n):
     if n == 1:
        return 1
     else:
        return n * factorial(n - 1)
  
  assert factorial(1)==1
  assert factorial(5)==120
  assert factorial(3)==6
  assert factorial(0)==1
  assert factorial(4)==24
output: def factorial(n):
     if n == 1:
        return 1
     else:
        return n * factorial(n - 1)