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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 output_files(self):
 """Returns all output files from all of the current module's rules."""

        for dep in self.subgraph.successors(self.address):
            dep_rule = self.subgraph.node[dep]['target_obj']
            for out_file in dep_rule.output_files:
                yield out_file