code: def test_heatmap():
      matrix_values = [[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]]
      x_labels = ["a", "b"]
      y_labels = ["A", "B", "C", "D", "E"]
      hm = heatmap(x_labels, y_labels, matrix_values)
  
      assert hm.value.data[4] == ["a", "E", 9]
  
file_path: wandb/tests/pytest_tests/unit_tests/test_plots.py
imports: import pytest
  from sklearn.naive_bayes import MultinomialNB
  from wandb.plots.heatmap import heatmap
  from wandb.plots.precision_recall import precision_recall
  from wandb.plots.roc import roc
label_desc: Use image node_id 4 for calling a global function with example usage: test_heatmap() without return types