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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 pop(self):
 """Pop an entry off the stack and make its node a child of the last."""

        dfa, state, node = self.stack.pop()
        if self.stack:
            self.stack[-1][2].children.append(node)
        else:
            self.root = node