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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def partition_pair(bif_point):
    '''Calculate the partition pairs at a bifurcation point

    The number of nodes in each child tree is counted. The partition
    pairs is the number of bifurcations in the two daughter subtrees
    at each branch point.'''
    n = float(sum(1 for _ in bif_point.children[0].ipreorder()))
    m = float(sum(1 for _ in bif_point.children[1].ipreorder()))
    return (n, m)