Only use platformdirs with Python >= '3.7'

gns3server/controller/appliance_manager.py

@@ -21,7 +21,6 @@ import uuid
 import asyncio
 import aiohttp
 import shutil
-import platformdirs
 
 
 try:
@@ -87,8 +86,14 @@ class ApplianceManager:
         Get the built-in appliance storage directory
         """
 
-        appname = vendor = "GNS3"
-        appliances_dir = os.path.join(platformdirs.user_data_dir(appname, vendor, roaming=True), "appliances")
+        try:
+            import platformdirs
+            appname = vendor = "GNS3"
+            appliances_dir = os.path.join(platformdirs.user_data_dir(appname, vendor, roaming=True), "appliances")
+        except ImportError:
+            # platformdirs is not available on Python 3.6, use the old method
+            config = Config.instance()
+            appliances_dir = os.path.join(config.config_dir, "appliances")
         if delete_first:
             shutil.rmtree(appliances_dir, ignore_errors=True)
         os.makedirs(appliances_dir, exist_ok=True)