fix #7

Author: Sorosliu1029

jupyterlab_leetcode/utils/notebook_generator.py

@@ -186,7 +186,12 @@ def fill_case(case):
             return f"s.{func_name}({case.replace('\n', ', ')})"
 
         for i, case in enumerate(cases):
-            # TODO: replace `null` with `None`
+            case = (
+                case.replace("null", "None")
+                .replace("true", "True")
+                .replace("false", "False")
+            )
+
             if i == 0:
                 run_cell["source"] = [f"s = Solution()\n{fill_case(case)}"]
             else: