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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 update_nodes(self, char, patch, backdate=False):
 """Change the stats of nodes in a character according to a dictionary. """

        if backdate:
            parbranch, parrev = self._real._parentbranch_rev.get(
                self._real.branch, ('trunk', 0)
            )
            tick_now = self._real.tick
            self._real.tick = parrev
        for i, (n, npatch) in enumerate(patch.items(), 1):
            self.update_node(char, n, npatch)
        if backdate:
            self._real.tick = tick_now