code: def test_difference_matrix_broadcasting_symmetric() -> None:
      X = np.random.randn(5, 4, 3, 2)
      d = difference_matrix(X, None)
      assert d.shape == (5, 4, 3, 3, 2)
  
file_path: GPflow/tests/gpflow/utilities/test_ops.py
imports: from typing import Union, cast
  import numpy
  import pytest
  import tensorflow
  from check_shapes import check_shapes
  import gpflow
  from gpflow.base import AnyNDArray
  from gpflow.utilities.ops import difference_matrix
label_desc: Use image node_id 3 for calling a global function with example usage: test_difference_matrix_broadcasting_symmetric() without return types