def margin_of_victory(value_list):
    """
    Accepts a list of numbers and returns the difference between
    the first place and second place values.

    This can be useful for covering elections as an easy to way to figure out
    the margin of victory for a leading candidate.

    h3. Example usage

        >> import calculate
        >> calculate.margin_of_victory([3285, 2804, 7170])
        3885
    """
    value_list.sort(reverse=True)
    return value_list[0] - value_list[1]
