Question: 
Write a function that takes two lists and returns true if they have at least one common element.


Model's Code:
def common_element(list1, list2):
    for element in list1:
        if element in list2:
            return True
    return None



Sample Correct Code:
def common_element(list1, list2):
     result = False
     for x in list1:
         for y in list2:
             if x == y:
                 result = True
                 return result


Asserts:
assert common_element([1,2,3,4,5], [5,6,7,8,9])==True
assert common_element([1,2,3,4,5], [6,7,8,9])==None
assert common_element(['a','b','c'], ['d','b','e'])==True


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

Test 431 of 974: 315/431 (73.08584686774941%): success