code: def test_flatten_output_shapes():
      flatten = Flatten()
      x = torch.randn(16, 3, 32, 32)
      output = flatten(x)
      assert output.shape == (16, 3072), "Unexpected output shape"
  
file_path: pykale/tests/embed/test_image_cnn.py
imports: import pytest
  import torch
  from kale.embed.image_cnn import Flatten, Identity, LeNet, ResNet18Feature, ResNet34Feature, ResNet50Feature, ResNet101Feature, ResNet152Feature, SimpleCNNBuilder, SmallCNNFeature
label_desc: Use image node_id 5 for calling a global function with example usage: test_flatten_output_shapes() without return types