code: def wait_for_single_device(self, timeout=None, interval=0.5):
      
  
      timer = TimeoutManager(timeout)
      with self._cond:
        # As long as there are no Myo's connected, wait until we
        # get notified about a change.
        while not timer.check():
          # Check if we found a Myo that is connected.
          for device in self._devices.values():
            if device.connected:
              return device
          self._cond.wait(timer.remainder(interval))
  
      return None
docs: Waits until a Myo is was paired **and** connected with the Hub and returns
      it. If the *timeout* is exceeded, returns None. This function will not
      return a Myo that is only paired but not connected.
  
      # Parameters
      timeout: The maximum time to wait for a device.
      interval: The interval at which the function should exit sleeping. We can
        not sleep endlessly, otherwise the main thread can not be exit, eg.
        through a KeyboardInterrupt.