Check if user exists and if alerts exist before attempting to list them

token_bot/tracker.py

@@ -191,7 +191,15 @@ class Tracker(Extension):
         description="List all alerts you have signed up for"
     )
     async def list_alerts(self, ctx: SlashContext):
+        if not await self._users.exists(ctx.user.id):
+            await ctx.send("You are not registered with any region\n"
+                           "Please register with /register before adding alerts",
+                           ephemeral=True)
+            return
         alerts = await self._users.list_alerts(ctx.user.id)
+        if len(alerts) == 0:
+            await ctx.send("You do not have any alerts registered", ephemeral=True)
+            return
         alerts_str = f"You have {len(alerts)} out of 25 maximum alerts registered"
         embeds = [Embed(
             title="List of TokenBot Tracker Alerts",