code: def __register_class(self, parsed_config):
      
      methods = parsed_config.get('methods')
      if not methods:
        return
  
      # Determine the name of the class that implements this configuration.
      service_classes = set()
      for method in methods.itervalues():
        rosy_method = method.get('rosyMethod')
        if rosy_method and '.' in rosy_method:
          method_class = rosy_method.split('.', 1)[0]
          service_classes.add(method_class)
  
      for service_class in service_classes:
        if service_class in self.__registered_classes:
          raise api_exceptions.ApiConfigurationError(
              'API class %s has already been registered.' % service_class)
        self.__registered_classes.add(service_class)
docs: Register the class implementing this config, so we only add it once.
  
      Args:
        parsed_config: The JSON object with the API configuration being added.
  
      Raises:
        ApiConfigurationError: If the class has already been registered.