docs: def stripascii(string):
      """Return string truncated at last byte that is 7-bit ASCII.
  
      Clean NULL separated and terminated TIFF strings.
  
      >>> stripascii(b'string\\x00string\\n\\x01\\x00')
      b'string\\x00string\\n'
      >>> stripascii(b'\\x00')
      b''
  
      """
      # TODO: pythonize this
      i = len(string)
      while i:
          i -= 1
          if 8 < byte2int(string[i]) < 127:
              break
      else:
          i = -1
      return string[:i+1]