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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 unroot(self):
 """ Returns a copy of the tree unrooted. Does not transform tree in-place. """

        nself = self.copy()
        nself.treenode.unroot()
        nself.treenode.ladderize()
        nself._coords.update()
        return nself