def AddRepositoryTags(prefix=''):
  """Add repository tagging into the output.

  Args:
    prefix: comment delimiter, if needed, to appear before tags
  Returns:
    list of text lines containing revision data
  """
  tags = []
  p4_id = '%sId:%s' % ('$', '$')
  p4_date = '%sDate:%s' % ('$', '$')
  tags.append('%s%s' % (prefix, p4_id))
  tags.append('%s%s' % (prefix, p4_date))
  return tags