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


Model's Code:
def binomial_coefficient(n, k):
    if k > n or k < 0:
        return 0
    if k == 0 or k == n:
        return 1
    return binomial_coefficient(n - 1, k - 1) + binomial_coefficient(n - 1, k)

def sum_Of_product(n):
    total_sum = 0
    for k in range(n + 1):
        total_sum += binomial_coefficient(n, k) * k
    return total_sum



Sample Correct Code:
def binomial_Coeff(n,k): 
    C = [0] * (k + 1); 
    C[0] = 1; # nC0 is 1 
    for i in range(1,n + 1):  
        for j in range(min(i, k),0,-1): 
            C[j] = C[j] + C[j - 1]; 
    return C[k]; 
def sum_Of_product(n): 
    return binomial_Coeff(2 * n,n - 1); 


Asserts:
assert sum_Of_product(3) == 15
assert sum_Of_product(4) == 56
assert sum_Of_product(1) == 1


Tests:
Test 1 of 3: FAIL: AssertionError()

Test 592 of 974: 439/592 (74.1554054054054%): failed