code: def _pre_process_line(line, comment_markers=_COMMENT_MARKERS):
      
      if not line:
          return None
  
      if any(c in line for c in comment_markers):
          if line.startswith(comment_markers):
              return None
  
      return line
docs: Preprocess a line in properties; strip comments, etc.
  
      :param line:
          A string not starting w/ any white spaces and ending w/ line breaks.
          It may be empty. see also: :func:`load`.
      :param comment_markers: Comment markers, e.g. '#' (hash)
  
      >>> _pre_process_line('') is None
      True
      >>> s0 = "calendar.japanese.type: LocalGregorianCalendar"
      >>> _pre_process_line("# " + s0) is None
      True
      >>> _pre_process_line("! " + s0) is None
      True
      >>> _pre_process_line(s0 + "# comment")
      'calendar.japanese.type: LocalGregorianCalendar# comment'