added warn purge command to help clear the warnings list when it gets too big.

roxbot/cogs/admin.py

@@ -205,6 +205,20 @@ class Admin():
 			except KeyError:
 				return await ctx.send("Could not find user in warning list.")
 
+	@commands.bot_has_permissions(ban_members=True)
+	@warn.command()
+	async def purge(self, ctx, dry_run=0):
+		"""Purges banned users from the warn list. Add a 1 at the end to do a dry run."""
+		settings = gs.get(ctx.guild)
+		count = 0
+		for ban in await ctx.guild.bans():
+			for user in settings.warnings:
+				if user == ban.user.id:
+					if not dry_run:
+						settings.warnings.pop(user)
+					count += 1
+		return await ctx.send("Purged {} banned users from the warn list.".format(count))
+
 	@commands.has_permissions(kick_members=True)
 	@commands.bot_has_permissions(kick_members=True)
 	@bot.command()