System clipboard getter/setter

clipboard.py

# Is this a stupid pattern?
def clipboard(text=None):
  '''
  Given no argument, returns the contents of the system clipboard or
  None if empty.
  Given an argument string, sets that as the value of the system clipboard and
  returns the given string.

  Note: The presence of calling this function will result in the system
  clipboard being flushed on program termination.
  '''
  try:
    _ = clipboard.win
  except AttributeError:
    import Tkinter
    win = Tkinter.Tk()
    win.withdraw()
    clipboard.win = win
    clipboard.TclError = Tkinter._tkinter.TclError
  if text is None:
    try:
      return clipboard.win.selection_get(selection='CLIPBOARD')
    except clipboard.TclError:
      return None
  else:
    clipboard.win.clipboard_clear()
    clipboard.win.clipboard_append(text)
    return text