diff --git a/rplugin/python3/deoplete/child.py b/rplugin/python3/deoplete/child.py
index bdbaa429..0cf1c6bf 100644
--- a/rplugin/python3/deoplete/child.py
+++ b/rplugin/python3/deoplete/child.py
@@ -554,7 +554,7 @@ def _set_source_attributes(self, context: UserContext) -> None:
     def _on_event(self, context: UserContext) -> None:
         event = context['event']
         for source_name, source in self._itersource(context):
-            if source.events is None or event in source.events:
+            if not source.events or event in source.events:
                 try:
                     source.on_event(context)
                 except Exception as exc: