code: def _set_min_level(self, handler_class, level):
          
          if self._exist_handler(handler_class):
              if not level:
                  self._delete_handler(handler_class)
              else:
                  self._update_handler(handler_class, level=level)
          elif level:
              self._create_handler(handler_class, level)
docs: Generic method to setLevel for handlers.