Fix overwriting of AuditLogDiff.roles for multiple $add/$remove keys

discord/audit_logs.py

@@ -165,6 +165,7 @@ class AuditLogChanges:
             self.before.color = self.before.colour
 
     def _handle_role(self, first, second, entry, elem):
+        if not hasattr(first, 'roles'):
             setattr(first, 'roles', [])
 
         data = []