docs: @Deprecated //TO BE REMOVED - should not be part of public API
      public SDVariable invoke(Op op, SDVariable x, SDVariable y) {
          if (!opMethods.containsKey(op.opName())) {
              throw new ND4JIllegalStateException("Illegal method opName " + op.opName());
          }
  
          if (x != null && y != null) {
              try {
                  return (SDVariable) opMethods.get(op.opName()).invoke(this, x, y);
              } catch (Exception e) {
  
              }
          } else {
              try {
                  return (SDVariable) opMethods.get(op.opName()).invoke(this, x);
              } catch (Exception e) {
  
              }
          }
  
          throw new ND4JIllegalStateException("Illegal method opName " + op.opName());
      }