def count_inversion(sequence):
    """
        Count inversions in a sequence of numbers
    """
    sequence = list(sequence)
    ordered_sequence = sorted(sequence)
    inversions = 0
    for index, number in enumerate(ordered_sequence):
        if sequence.index(number) == index:
            continue
        inversions += sequence.index(number) - index
        sequence.insert(index, sequence.pop(sequence.index(number)))
    return inversions


if __name__ == '__main__':
    print("Example:")
    print(count_inversion([1, 2, 5, 3, 4, 7, 6]))

    # These "asserts" using only for self-checking and not necessary for auto-testing
    assert count_inversion((1, 2, 5, 3, 4, 7, 6)) == 3, "Example"
    assert count_inversion((0, 1, 2, 3)) == 0, "Sorted"
    assert count_inversion((5, 3, 2, 1, 0)) == 10, "Reversed"
    assert count_inversion((99, -99)) == 1, "Two numbers"
    print("Coding complete? Click 'Check' to review your tests and earn cool rewards!")