human
Complete this python program:
def hypervolume(front, **kargs):
assistant
#Here is the Python code you requested.

    """Returns the index of the individual with the least the hypervolume
    contribution. The provided *front* should be a set of non-dominated
    individuals having each a :attr:`fitness` attribute.
    """
    wobj = (numpy.array([ind.fitness.wvalues for ind in front]) * (-1))
    ref = kargs.get('ref', None)
    if (ref is None):
        ref = (numpy.max(wobj, axis=0) + 1)
    def contribution(i):
        return hv.hypervolume(numpy.concatenate((wobj[:i], wobj[(i + 1):])), ref)
    contrib_values = map(contribution, range(len(front)))
    return numpy.argmax(contrib_values)