From 2c6126c2a17003eb4083b9509fc009f71c65e76f Mon Sep 17 00:00:00 2001
From: Rapptz <Rapptz@gmail.com>
Date: Wed, 6 Jan 2016 18:27:11 -0500
Subject: [PATCH] [commands] None default without specified type uses str now.

---
 discord/ext/commands/core.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/discord/ext/commands/core.py b/discord/ext/commands/core.py
index 92ff64ab6..ef2a3b156 100644
--- a/discord/ext/commands/core.py
+++ b/discord/ext/commands/core.py
@@ -137,7 +137,7 @@ class Command:
 
         if converter is param.empty:
             if not required:
-                converter = type(param.default)
+                converter = str if param.default is None else type(param.default)
             else:
                 converter = str
         elif not inspect.isclass(type(converter)):