diff --git a/src/coffea/nanoevents/methods/nanoaod.py b/src/coffea/nanoevents/methods/nanoaod.py
index 184377427..322eb6bd0 100644
--- a/src/coffea/nanoevents/methods/nanoaod.py
+++ b/src/coffea/nanoevents/methods/nanoaod.py
@@ -13,13 +13,16 @@
 
 class _NanoAODEvents(behavior["NanoEvents"]):
     def __repr__(self):
-        if (hasattr(self,"run") and
-                hasattr(self,"luminosityBlock") and
-                hasattr(self,"event")):
+        if (
+            hasattr(self, "run")
+            and hasattr(self, "luminosityBlock")
+            and hasattr(self, "event")
+        ):
             return f"<event {self.run}:{self.luminosityBlock}:{self.event}>"
         else:
             return "<event>"
 
+
 behavior["NanoEvents"] = _NanoAODEvents