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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 clone(self, substitutions, **kwargs):
 """ Clone a DAG. """

        dag = self.explain(**kwargs)
        dag.substitutions.update(substitutions)
        cloned_dag = dag.clone(ignore=self.ignore)
        return self.update_nodes(self.add_edges(cloned_dag))