Prompt the user for the next action.

    Returns:
      A string, the character entered by the user.

def _AskUser(self):
    """Prompt the user for the next action.

    Returns:
      A string, the character entered by the user.
    """
    if self._show_percent:
      progress = int(self._displayed*100 / (len(self._text.splitlines())))
      progress_text = ' (%d%%)' % progress
    else:
      progress_text = ''
    question = AnsiText(
        'Enter: next line, Space: next page, '
        'b: prev page, q: quit.%s' %
        progress_text, ['green'])
    sys.stdout.write(question)
    sys.stdout.flush()
    ch = self._GetCh()
    sys.stdout.write('\r%s\r' % (' '*len(question)))
    sys.stdout.flush()
    return ch