def METHOD_NAME(bif_point, iterator_type=Section.ipreorder):
    """Calculate the partition at a bifurcation point.
    We first ensure that the input point has only two children.
    The number of nodes in each child tree is counted. The partition is
    defined as the ratio of the largest number to the smallest number.
    """
    _raise_if_not_bifurcation(bif_point)
    n, m = partition_pair(bif_point, iterator_type=iterator_type)
    return max(n, m) / min(n, m)