Fix some python3 issues

- (str, unicode) instead of six.string_types
- binary/text conversion on None

disco/bot/bot.py

@@ -141,7 +141,7 @@ class Bot(LoggingClass):
                 self.client.events.on('MessageUpdate', self.on_message_update)
 
         # If we have a level getter and its a string, try to load it
-        if isinstance(self.config.commands_level_getter, (str, unicode)):
+        if isinstance(self.config.commands_level_getter, six.string_types):
             mod, func = self.config.commands_level_getter.rsplit('.', 1)
             mod = importlib.import_module(mod)
             self.config.commands_level_getter = getattr(mod, func)

disco/types/base.py

@@ -207,6 +207,9 @@ def datetime(data):
 
 
 def text(obj):
+    if obj is None:
+        return None
+
     if six.PY2:
         if isinstance(obj, str):
             return obj.decode('utf-8')
@@ -216,6 +219,9 @@ def text(obj):
 
 
 def binary(obj):
+    if obj is None:
+        return None
+
     if six.PY2:
         if isinstance(obj, str):
             return obj.decode('utf-8')