code: def get_3d_input(self):
      input_shape = (2, 16, 16, 16, 8)
      x_3d = tf.ones(input_shape)
      return x_3d
  
imports: from __future__ import division, absolute_import, print_function
  import functools
  import numpy
  import tensorflow
  from tensorflow.contrib.layers.python.layers import regularizers
  from niftynet.layer.convolution import ConvLayer
  from niftynet.layer.convolution import ConvolutionalLayer
  from tests.niftynet_testcase import NiftyNetTestCase
label_desc: Use image node_id 1 for calling the ConvTest obj's underlying member method code with example usage: obj.get_3d_input() and returns: x_3d