code: def add_range_headers(self, range_header):
          
          self['Accept-Ranges'] = 'bytes'
          size = self.ranged_file.size
          try:
              ranges = self.ranged_file.parse_range_header(range_header, size)
          except ValueError:
              ranges = None
          # Only handle syntactically valid headers, that are simple (no
          # multipart byteranges).
          if ranges is not None and len(ranges) == 1:
              start, stop = ranges[0]
              if start >= size:
                  # Requested range not satisfiable.
                  self.status_code = 416
                  return
  
              if stop >= size:
                  stop = size
  
              self.ranged_file.start = start
              self.ranged_file.stop = stop
              self['Content-Range'] = 'bytes %d-%d/%d' % (start, stop - 1, size)
              self['Content-Length'] = stop - start
              self.status_code = 206
docs: Adds several headers that are necessary for a streaming file
          response, in order for Safari to play audio files. Also
          sets the HTTP status_code to 206 (partial content).
  
          Args:
              range_header (str): Browser HTTP_RANGE request header.