docs: def wait_key(keys=None):
      ''' Waits for a keypress at the console and returns it.
          "Where's the any key?"
  
          Arguments:
              keys - if passed, wait for this specific key, e.g. ESC.
                     may be a tuple.
          Returns:
              char or ESC - depending on key hit.
              None - immediately under i/o redirection, not an interactive tty.
      '''
      if is_a_tty():
          if keys:
              if not isinstance(keys, tuple):
                  keys = (keys,)
              while True:
                  key = _getch()
                  if key in keys:
                      return key
          else:
              return _getch()