def handle_title_string(title_line):
  """Find the title and (if it exists) the auxiliary title information.

  Args:
    title_line: line of FASTQ file containing the title.  Starts with '@'.

  Returns:
    title (string).
    title_aux (string, which is "" if there is no auxiliary information).
  """
  # Strip off leading "@"; only go to first space character.
  #
  # Although the standard specifies that there should be no spaces, in practice
  # the title string looks like:
  #
  # <true sequence record title>[space character]<extra info>
  #
  # where "extra info" is things like barcode index read.
  title_pieces = title_line[1:].split()
  title = title_pieces[0]
  title_aux = ""
  if len(title_pieces) > 1:
    title_aux = " ".join(title_pieces[1:])
  return title, title_aux