code: def test_comment():
      tracker = SQLiteTracker(":memory:")
      uuid = tracker.new()
      tracker.comment(uuid, "this is a comment")
      res = tracker[uuid]
  
      assert res.loc[uuid].comment == "this is a comment"
  
imports: import json
  from uuid import uuid4
  import time
  import pytest
  from sklearn_evaluation.tracker import SQLiteTracker
  from sklearn_evaluation import tracker
  from sklearn_evaluation import plot
label_desc: Use image node_id 3 for calling a global function with example usage: test_comment() without return types