code: def test_3d_softsign_shape(self):
      self.run_test(True, "softsign", (2, 16, 16, 16, 8))
  
imports: from __future__ import absolute_import, print_function
  import tensorflow
  from tensorflow.contrib.layers.python.layers import regularizers
  from niftynet.layer.activation import ActiLayer
  from tests.niftynet_testcase import NiftyNetTestCase
label_desc: Use image node_id 9 for calling the ActivationTest obj's underlying member method code with example usage: obj.test_3d_softsign_shape() without return types