def largest_odd_times(L):
    """ Assumes L is a non-empty list of ints
        Returns the largest element of L that occurs an odd number 
        of times in L. If no such element exists, returns None """
    l = L.copy()
    l.sort()
    l.reverse()
    for x in l:
        if l.count(x) % 2:
            return x
    return None