code: def get_level_methods(self, level):
          
          try:
              # Real name of the level
              return set(self.__levels[level])
          except KeyError:
              # Alias
              result = set()
              for sub_level in self.__aliases[level]:
                  result.update(self.get_level_methods(sub_level))
              return result
docs: Returns the methods to call for the given level of report
  
          :param level: The level of report
          :return: The set of methods to call to fill the report
          :raise KeyError: Unknown level or alias