Guard against Python 3.9

notebooks/PythonFuzzer.ipynb

@@ -10,6 +10,7 @@
     "# Testing Compilers\n",
     "\n",
     "In this chapter, we will make use of [grammars and grammar-based testing](Grammars.ipynb) to systematically generate _program code_ – for instance, to test a compiler or an interpreter. Not very surprising, we use _Python_ and the _Python interpreter_ as our domain.\n",
+    "\n",
     "We chose Python not only because the rest of the book is also based on Python.\n",
     "Most importantly, Python brings lots of built-in infrastructure we can leverage, especially _parsers_ that convert Python code into an abstract syntax tree (AST) representation, and _unparsers_ that take an AST and convert it back into Python code.\n",
     "This allows us to leverage grammars that operate on ASTs rather than concrete syntax, greatly reducing complexity."
@@ -25,6 +26,30 @@
     "* You must read the chapter on [Fuzzing with Grammars](Grammars.ipynb) to understand how grammars and grammar-based testing work."
    ]
   },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "9eadd112",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# ignore\n",
+    "import sys"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "4cea401a",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# ignore\n",
+    "if sys.version_info < (3, 10):\n",
+    "    print(\"This code requires Python 3.10 or later\")\n",
+    "    sys.exit(0)"
+   ]
+  },
   {
    "cell_type": "markdown",
    "id": "6891d8a0",