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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 get_doc(self, name):
 """ Retrieve a ``RuleDoc`` object from the ``Policy`` with the given name. The ``RuleDoc`` object contains all documentation for the named rule. :param name: The name of the rule to retrieve the documentation for. :returns: A ``RuleDoc`` object containing the documentation for the rule. """


        # Create one if there isn't one already
        if name not in self._docs:
            self._docs[name] = rules.RuleDoc(name)

        return self._docs[name]