code: def from_stat(cls, obj, filename=None):
          
          attr = cls()
          attr.st_size = obj.st_size
          attr.st_uid = obj.st_uid
          attr.st_gid = obj.st_gid
          attr.st_mode = obj.st_mode
          attr.st_atime = obj.st_atime
          attr.st_mtime = obj.st_mtime
          if filename is not None:
              attr.filename = filename
          return attr
docs: Create an `.SFTPAttributes` object from an existing ``stat`` object (an
          object returned by `os.stat`).
  
          :param object obj: an object returned by `os.stat` (or equivalent).
          :param str filename: the filename associated with this file.
          :return: new `.SFTPAttributes` object with the same attribute fields.