Question: 
Write a python function to find the sum of all even natural numbers within the range l and r.


Model's Code:
def sum_Even(l, r):
    return sum(i for i in range(l, r + 1) if i % 2 == 0)



Sample Correct Code:
def sum_Natural(n): 
    sum = (n * (n + 1)) 
    return int(sum) 
def sum_Even(l,r): 
    return (sum_Natural(int(r / 2)) - sum_Natural(int((l - 1) / 2))) 


Asserts:
assert sum_Even(2,5) == 6
assert sum_Even(3,8) == 18
assert sum_Even(4,6) == 10


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

Test 962 of 974: 736/962 (76.50727650727652%): success