code: def test_init(self):
      self.assertIs(self.mlp.activation, functions.sigmoid)
      self.assertEqual(len(self.mlp), 3)
  
imports: import unittest
  import mock
  import numpy
  import chainer
  from chainer.backends import cuda
  from chainer import functions
  from chainer import links
  from chainer import testing
  from chainer.testing import attr
label_desc: Use image node_id 2 for calling the TestMLPConvolution2DShapePlaceholder obj's underlying member method code with example usage: obj.test_init() without return types