title: Python List Append with bumpy array error
body: <p>I am trying to use list append function to append a list to a list. </p>
  
  <p>But got error shows list indices must be integers or slices, not tuple. Not sure why. </p>
  
  <pre><code>pca_components = range(1,51)
  gmm_components = range(1,5)
  covariance_types = ['spherical', 'diag', 'tied', 'full']
  
  # Spherical
  spherical_results = []
  for i in pca_components:
      pca_model = PCA(n_components=i)
      pca_train = pca_model.fit(train_data).transform(train_data)
      for j in gmm_components:
          parameters = (i+i)*j*2
          if parameters &gt; 50:
              pass
          else:             
              gmm_model = GMM(n_components=j, covariance_type='spherical')
              gmm_model.fit(pca_train)
              pca_test = pca_model.transform(test_data)
              predictions = gmm_model.predict(pca_test)
              accuracy = np.mean(predictions.ravel() == test_labels.ravel())
              accuracy=int(accuracy)
              spherical_results.append([accuracy, i,j, parameters])
  spher_results = np.array(spherical_results)
  max_accuracy = np.amax(spherical_results[:,0])
  print(f"highest accuracy score for spherical is {max_accuracy}")
  </code></pre>