Question: 
Write a python function to find the sum of squares of binomial co-efficients.


Model's Code:
def sum_of_square(n):
    from math import comb
    return sum(comb(n, k) ** 2 for k in range(n + 1))



Sample Correct Code:
def factorial(start,end): 
    res = 1 
    for i in range(start,end + 1): 
        res *= i      
    return res 
def sum_of_square(n): 
   return int(factorial(n + 1, 2 * n)  /factorial(1, n)) 


Asserts:
assert sum_of_square(4) == 70
assert sum_of_square(5) == 252
assert sum_of_square(2) == 6


Tests:
Test 1 of 3: PASS
Test 2 of 3: PASS
Test 3 of 3: PASS

Test 905 of 974: 698/905 (77.12707182320442%): success