code: def wait_until(self, s, timeout=None):
          
          return self.wait(lambda state: s in state, timeout)
docs: Blocks until ``s`` is in ``self.state``.  The condition is checked when
          there is an I/O event related to the ``state`` attribute.  Exits early
          when ``timeout`` (in milliseconds) is reached.
  
          Returns ``True`` if the condition is met, and ``False`` if the timeout
          is reached.
  
          Example::
  
              m.wait_until('stalled')