code: public void removeTangoAttConfigListener(ITangoAttConfigListener listener, String attrName)
              throws DevFailed {
          synchronized (moni) {
              TangoAttConfig tangoAttConfig;
              String key = deviceName+"/"+attrName;
              if ((tangoAttConfig = tango_att_config_source.get(key)) != null)
                  tangoAttConfig.removeTangoAttConfigListener(listener);
          }
      }
docs: =======================================================================