diff.py

def diff_a(a, b):
    return list(set(a) - set(b)) + list(set(b) - set(a))

def diff_b(lists):
    x = [list(set(i) - set(j)) for i in lists for j in lists]
    return list(set([item for sublist in x for item in sublist]))

def main():
    a = [1, 2, 3]; b = [1, 2, 5, 4]; c = [1, 3, 5, 6]
    print(diff_a(a, b))      # [3, 5, 4]
    print(diff_b([a, b, c])) # [2, 3, 4, 5, 6]

if __name__ == '__main__':
    main()

wat