Changed functions that return a constant value into properties.

discord/channel.py

@@ -99,6 +99,7 @@ class Channel:
         """bool : Indicates if this is the default channel for the :class:`Server` it belongs to."""
         return self.server.id == self.id
 
+    @property
     def mention(self):
         """str : The string that allows you to mention the channel."""
         return '<#{0.id}>'.format(self)

discord/server.py

@@ -141,6 +141,7 @@ class Server:
         """Gets the default :class:`Channel` for the server."""
         return utils.find(lambda c: c.is_default_channel(), self.channels)
 
+    @property
     def icon_url(self):
         """Returns the URL version of the server's icon. Returns an empty string if it has no icon."""
         if self.icon is None:

discord/user.py

@@ -68,6 +68,7 @@ class User(object):
             return other.id != self.id
         return False
 
+    @property
     def avatar_url(self):
         """Returns a friendly URL version of the avatar variable the user has. An empty string if
         the user has no avatar."""
@@ -75,6 +76,7 @@ class User(object):
             return ''
         return 'https://discordapp.com/api/users/{0.id}/avatars/{0.avatar}.jpg'.format(self)
 
+    @property
     def mention(self):
         """Returns a string that allows you to mention the given user."""
         return '<@{0.id}>'.format(self)