code: def discover_config_path(self, config_filename: str) -> str:
          
  
          if config_filename and os.path.isfile(config_filename):
              return config_filename
  
          for place in _common_places:
              config_path = os.path.join(place, config_filename)
              if os.path.isfile(config_path):
                  return config_path
  
          return
docs: Search for config file in a number of places.
          If there is no config file found, will return None.
  
          :param config_filename: Config file name or custom path to filename with config.
          :return: Path to the discovered config file or None.