code: public static boolean exists(String deviceName) throws DevFailed {
          //	Get full device name (with tango host) to manage multi tango_host
          String fullDeviceName = new TangoUrl(deviceName).toString();
  
          //	Get it if already exists
          DeviceProxy dev = proxy_table.get(fullDeviceName);
          return (dev != null);
      }
docs: ===================================================================