docs: def resolve_upload_path(self, filename=None):
          """Resolve upload path for use with the executor.
  
          :param filename: Filename to resolve
          :return: Resolved filename, which can be used to access the
              given uploaded file in programs executed using this
              executor
          """
          if filename is None:
              return constants.UPLOAD_VOLUME
  
          return os.path.join(constants.UPLOAD_VOLUME, filename)