code: private EventConsumer isChannelAlreadyConnected(DeviceProxy deviceProxy) {
          try {
              String adminName = deviceProxy.adm_name();
              EventChannelStruct eventChannelStruct = EventConsumer.getChannelMap().get(adminName);
              if (eventChannelStruct==null) {
                  return null;
              }
              else {
                  return eventChannelStruct.consumer;
              }
          }
          catch (DevFailed e) {
              return null;
          }
      }
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