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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 pretty_print_config_to_json(self, configs):
 """JSON string description of a protorpc.remote.Service in a discovery doc. Args: configs: Either a single dict or a list of dicts containing the service configurations to list. Returns: string, The directory list document as a JSON string. """

    descriptor = self.get_directory_list_doc(configs)
    return json.dumps(descriptor, sort_keys=True, indent=2,
                      separators=(',', ': '))