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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 touch(self, edited=False):
 """Mark the node as dirty. Args: edited (bool):
 Whether to set the edited time. """

        self._dirty = True
        dt = datetime.datetime.utcnow()
        self.timestamps.updated = dt
        if edited:
            self.timestamps.edited = dt