fetch user with discord database when it failed if the cache

src/cogs/utils.py

@@ -387,6 +387,8 @@ class Utils(commands.Cog):
         if user == None:
             return await self._whois(ctx, True)
         else:
+            if isinstance(user, int):
+                user = await self.client.fetch_user(user)
             return await self._whois(ctx, user, True)
 
     @commands.command(name='sondage')