code: @Override
      public INDArray convn(INDArray input, INDArray kernel, Convolution.Type type, int[] axes) {
          throw new UnsupportedOperationException();
      }
docs: ND Convolution
  
  @param input  the input to op
  @param kernel the kernel to op with
  @param type   the opType of convolution
  @param axes   the axes to do the convolution along
  @return the convolution of the given input and kernel