Question: 
Write a function to find the difference of first even and odd number of a given list.


Model's Code:
def diff_even_odd(lst):
    even = next((x for x in lst if x % 2 == 0), None)
    odd = next((x for x in lst if x % 2 != 0), None)
    if even is not None and odd is not None:
        return even - odd
    return None



Sample Correct Code:
def diff_even_odd(list1):
    first_even = next((el for el in list1 if el%2==0),-1)
    first_odd = next((el for el in list1 if el%2!=0),-1)
    return (first_even-first_odd)


Asserts:
assert diff_even_odd([1,3,5,7,4,1,6,8])==3
assert diff_even_odd([1,2,3,4,5,6,7,8,9,10])==1
assert diff_even_odd([1,5,7,9,10])==9


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

Test 594 of 974: 441/594 (74.24242424242425%): success