code: def test_coulomb_fit_transformer():
      """Test coulomb fit transformer on singletask dataset."""
      n_samples = 10
      n_features = 3
      n_tasks = 1
      ids = np.arange(n_samples)
      X = np.random.rand(n_samples, n_features, n_features)
      y = np.zeros((n_samples, n_tasks))
      w = np.ones((n_samples, n_tasks))
      dataset = dc.data.NumpyDataset(X, y, w, ids)
      fit_transformer = dc.trans.CoulombFitTransformer(dataset)
      X_t = fit_transformer.X_transform(dataset.X)
      assert len(X_t.shape) == 2
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_coulomb_fit_transformer() without return types