Consider function calling roles and messages valid (#765)

examples/Chat_finetuning_data_prep.ipynb

@@ -123,14 +123,16 @@
     "        if \"role\" not in message or \"content\" not in message:\n",
     "            format_errors[\"message_missing_key\"] += 1\n",
     "        \n",
-    "        if any(k not in (\"role\", \"content\", \"name\") for k in message):\n",
+    "        if any(k not in (\"role\", \"content\", \"name\", \"function_call\") for k in message):\n",
     "            format_errors[\"message_unrecognized_key\"] += 1\n",
     "        \n",
-    "        if message.get(\"role\", None) not in (\"system\", \"user\", \"assistant\"):\n",
+    "        if message.get(\"role\", None) not in (\"system\", \"user\", \"assistant\", \"function\"):\n",
     "            format_errors[\"unrecognized_role\"] += 1\n",
     "            \n",
     "        content = message.get(\"content\", None)\n",
-    "        if not content or not isinstance(content, str):\n",
+    "        function_call = message.get(\"function_call\", None)\n",
+    "        \n",
+    "        if (not content and not function_call) or not isinstance(content, str):\n",
     "            format_errors[\"missing_content\"] += 1\n",
     "    \n",
     "    if not any(message.get(\"role\", None) == \"assistant\" for message in messages):\n",