@classmethod
def is_connected(cls, port, address='A'):
    """Return True if the specified port is connected to this device.

        This class can be used to automatically identify ports with connected
        Alicats. Iterate through all connected interfaces, and use this to
        test. Ports that come back True should be valid addresses.

        Note that this distinguishes between `FlowController` and `FlowMeter`.
        """
    is_device = False
    try:
        device = cls(port, address)
        try:
            c = device.get()
            if cls.__name__ == 'FlowMeter':
                assert c and 'setpoint' not in device.keys
            elif cls.__name__ == 'FlowController':
                assert c and 'setpoint' in device.keys
            else:
                raise NotImplementedError('Must be meter or controller.')
            is_device = True
        finally:
            device.close()
    except Exception:
        pass
    return is_device
