code: @Override
      public long opHash() {
          if (hash == 0) {
              val map = Nd4j.getExecutioner().getCustomOperations();
              val desc = map.get(opName());
              if (desc == null) {
                  throw new ND4JIllegalStateException("Op name " + opName() + " is missing!");
              }
  
              hash = desc.getHash();
          }
  
          return hash;
      }
docs: This method returns LongHash of the opName()
  
  @return