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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 reentrancies(self):
 """ Return a mapping of variables to their re-entrancy count. A re-entrancy is when more than one edge selects a node as its target. These graphs are rooted, so the top node always has an implicit entrancy. Only nodes with re-entrancies are reported, and the count is only for the entrant edges beyond the first. Also note that these counts are for the interpreted graph, not for the linearized form, so inverted edges are always re-entrant. """

        entrancies = defaultdict(int)
        entrancies[self.top] += 1  # implicit entrancy to top
        for t in self.edges():
            entrancies[t.target] += 1
        return dict((v, cnt - 1) for v, cnt in entrancies.items() if cnt >= 2)