Update guild.py (#7)

* Update guild.py

Server currently returns None for guilds with no channels, which causes `TypeError: 'NoneType' object is not iterable`
Fix this by making the None returned by the server into an empty list, getting rid of the error

* Update guild.py

Fix TypeError on iterating through None

ferris/guild.py

@@ -35,13 +35,13 @@ def _process_data(self, data: Data, /) -> None:
 
         self._channels: Dict[int, Channel] = {}
 
-        for c in data.get('channels', []):
+        for c in data.get('channels') or []:
             channel = Channel(self._connection, c)
             self._channels[channel.id] = channel
 
         self._members: Dict[int, Member] = {}
 
-        for m in data.get('members', []):
+        for m in data.get('members') or []:
             member = Member(self._connection, m)
             self._members[member.id] = member