[Core V3] Fix checks (#924)

* Fix global checks

* Fix bank's checks

Predicates for decorators return true or false, they don't return other decorators

* Async getters in core checks

core/global_checks.py

@@ -1,3 +1,4 @@
+"""The checks in this module run on every command."""
 from discord.ext import commands
 
 
@@ -5,22 +6,26 @@ def init_global_checks(bot):
 
     @bot.check
     async def global_perms(ctx):
+        """Check the user is/isn't globally whitelisted/blacklisted."""
         if await bot.is_owner(ctx.author):
             return True
 
-        if bot.db.whitelist():
-            return ctx.author.id in bot.db.whitelist()
+        whitelist = await bot.db.whitelist()
+        if whitelist:
+            return ctx.author.id in whitelist
 
-        return ctx.author.id not in bot.db.blacklist()
+        return ctx.author.id not in await bot.db.blacklist()
 
     @bot.check
     async def local_perms(ctx: commands.Context):
+        """Check the user is/isn't locally whitelisted/blacklisted."""
         if await bot.is_owner(ctx.author):
             return True
-        elif ctx.message.guild is None:
+        elif ctx.guild is None:
             return True
-        local_blacklist = bot.db.guild(ctx.guild).blacklist()
-        local_whitelist = bot.db.guild(ctx.guild).whitelist()
+        guild_settings = bot.db.guild(ctx.guild)
+        local_blacklist = await guild_settings.blacklist()
+        local_whitelist = await guild_settings.whitelist()
 
         if local_whitelist:
             return ctx.author.id in local_whitelist
@@ -29,4 +34,5 @@ def init_global_checks(bot):
 
     @bot.check
     async def bots(ctx):
+        """Check the user is not another bot."""
         return not ctx.author.bot