Add methods for creating sub-channels on a category

disco/types/channel.py

@@ -441,6 +441,34 @@ class Channel(SlottedModel, Permissible):
             parent_id=to_snowflake(parent) if parent else parent,
             reason=reason)
 
+    def create_text_channel(self, *args, **kwargs):
+        """
+        Creates a sub-text-channel in this category. See `Guild.create_text_channel`
+        for arguments and more information.
+        """
+        if self.type != ChannelType.GUILD_CATEGORY:
+            raise ValueError('Cannot create a sub-channel on a non-category channel')
+
+        kwargs['parent_id'] = self.id
+        return self.guild.create_text_channel(
+            *args,
+            **kwargs
+        )
+
+    def create_voice_channel(self, *args, **kwargs):
+        """
+        Creates a sub-voice-channel in this category. See `Guild.create_voice_channel`
+        for arguments and more information.
+        """
+        if self.type != ChannelType.GUILD_CATEGORY:
+            raise ValueError('Cannot create a sub-channel on a non-category channel')
+
+        kwargs['parent_id'] = self.id
+        return self.guild.create_voice_channel(
+            *args,
+            **kwargs
+        )
+
 
 class MessageIterator(object):
     """

examples/basic_plugin.py

@@ -15,8 +15,8 @@ class BasicPlugin(Plugin):
     @Plugin.command('create-some-channels')
     def on_create_some_channels(self, event):
         category = event.guild.create_category('My Category')
-        event.guild.create_text_channel('text-channel', parent_id=category.id)
+        category.create_text_channel('text-channel')
-        event.guild.create_voice_channel('voice-channel', parent_id=category.id)
+        category.create_voice_channel('voice-channel')
         event.msg.reply('Ok, created some channels')
 
     @Plugin.command('ratelimitme')