code: def set_logger(self, logger_name, level, handler=None):
          
          if 'loggers' not in self.config:
              self.config['loggers'] = {}
          real_level = self.real_level(level)
          self.config['loggers'][logger_name] = {'level': real_level}
          if handler:
              self.config['loggers'][logger_name]['handlers'] = [handler]
docs: Sets the level of a logger