Function factorial

Python/5 recusrion problems.py:3–8

(n)

# 1..TO FIND FACTORIAL OF A NUMBER USING RECURSION

def factorial(n):
    assert n>=0 and int(n)==n , "the number must be positive integer only"
    if n==0 or n==1:
        return 1
    else:
        return n*factorial(n-1)

print(factorial(4))