code: def test_flatten(self):
      class CustomizeModel(tl.models.Model):
          def __init__(self):
              super(CustomizeModel, self).__init__()
              self.flatten = tl.layers.Flatten()
  
          def forward(self, x):
              return self.flatten(x)
  
      model = CustomizeModel()
      print(model.flatten)
      model.train()
      out = model(self.data)
      self.assertEqual(out.get_shape().as_list(), [8, 12])
  
file_path: TensorLayer/tests/layers/test_layers_shape.py
imports: import os
  import unittest
  import numpy
  import tensorflow
  import tensorlayer
  from tests.utils import CustomTestCase
label_desc: Use image node_id 3 for calling the Layer_Shape_Test obj's underlying member method code with example usage: obj.test_flatten() and returns: self