Added type checks for ConditionTracer classes

notebooks/Tracer.ipynb

@@ -940,6 +940,7 @@
     "\n",
     "        if condition is None:\n",
     "            condition = 'False'\n",
+    "        assert isinstance(condition, str)\n",
     "\n",
     "        self.condition: str = condition\n",
     "        self.last_report: Optional[bool] = None\n",
@@ -1198,6 +1199,7 @@
     "    def __init__(self, *, condition: Optional[str] = None,\n",
     "                 events: List[str] = [], file: TextIO = sys.stdout) -> None:\n",
     "        \"\"\"Constructor. `events` is a list of expressions to watch.\"\"\"\n",
+    "        assert isinstance(events, List)  # avoid type errors\n",
     "        self.events = events\n",
     "        self.last_event_values: Dict[str, Any] = {}\n",
     "        super().__init__(file=file, condition=condition)"