text: from xonsh.completers.man import complete_from_man
  from xonsh.completers.path import complete_dir
  
  
  def complete_cd(prefix, line, start, end, ctx):
      """
      Completion for "cd", includes only valid directory names.
      """
      if start != 0 and line.split(" ")[0] == "cd":
          results, prefix = complete_dir(prefix, line, start, end, ctx, True)
          if len(results) == 0:
              raise StopIteration
          return results, prefix
      return set()
  
  
  def complete_rmdir(prefix, line, start, end, ctx):
      """
      Completion for "rmdir", includes only valid directory names.
      """
      if start != 0 and line.split(" ")[0] == "rmdir":
          opts = {
              i
              for i in complete_from_man("-", "rmdir -", 6, 7, ctx)
              if i.startswith(prefix)
          }
          comps, lp = complete_dir(prefix, line, start, end, ctx, True)
          if len(comps) == 0 and len(opts) == 0:
              raise StopIteration
          return comps | opts, lp
      return set()
  