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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 as_yaml(self):
 """ Render the YAML node and subnodes as string. """

        dumped = dump(self.as_marked_up(), Dumper=StrictYAMLDumper, allow_unicode=True)
        return dumped if sys.version_info[0] == 3 else dumped.decode("utf8")