any and generator expression

# Before
def contains_duplicate(array):
    for i in range(len(array)):
        for j in range(i):
            if array[i] == array[j]:
                return True
    return False

# After
def contains_duplicate(array):
    return any(
        array[i] == array[j]
        for i in range(len(array))
        for j in range(i)
    )