Slots use tuples instead now.

discord/mixins.py

@@ -25,7 +25,7 @@ DEALINGS IN THE SOFTWARE.
 """
 
 class EqualityComparable:
-    __slots__ = []
+    __slots__ = ()
 
     def __eq__(self, other):
         return isinstance(other, self.__class__) and other.id == self.id
@@ -36,7 +36,7 @@ class EqualityComparable:
         return True
 
 class Hashable(EqualityComparable):
-    __slots__ = []
+    __slots__ = ()
 
     def __hash__(self):
         return hash(self.id)