Add custom checks for permissions

Author: kyb3r

core/checks.py

@@ -0,0 +1,24 @@
+from discord.ext import commands
+
+def has_permissions(**perms):
+    """Check if the author has required permissions.
+    This will always return ``True`` if the author is a bot owner, or
+    has the ``administrator`` permission.
+    """
+    async def predicate(ctx):
+        if await ctx.bot.is_owner(ctx.author):
+            return True
+
+        resolved = ctx.channel.permissions_for(ctx.author)
+
+        return resolved.administrator or all(
+            getattr(resolved, name, None) == value for name, value in perms.items()
+        )
+    
+    return commands.check(predicate)
+
+def thread_only():
+    """Checks if the command is being run in a modmail thread"""
+    async def predicate(ctx):
+        return ctx.thread is not None
+    return commands.check(predicate)