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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 create_completer_query(self, service_name):
 """Create a CompleterDescriber for a service. :type service_name: str :param service_name: The name of the service, e.g. 'ec2' :return: A CompleterDescriber object. """

        if service_name not in self._describer_cache:
            query = self._create_completer_query(service_name)
            self._describer_cache[service_name] = query
        return self._describer_cache[service_name]