mypy: fixup for fastavro 1.9

ampel/ztf/dev/ZTFAlert.py

@@ -123,4 +123,10 @@ def _load_alert(cls, file_path: str) -> None | dict:
 	def _deserialize(f) -> None | dict:
 		""" """
 		reader = fastavro.reader(f)
-		return next(reader, None)
+		alert = next(reader, None)
+		if alert is None:
+			return alert
+		else:
+			assert isinstance(alert, dict)
+			return alert
+

ampel/ztf/t0/load/UWAlertLoader.py

@@ -65,6 +65,7 @@ def alerts(self, limit: None | int = None) -> Iterator[io.BytesIO]:
         for message in itertools.islice(self._consumer, limit):
             reader = fastavro.reader(io.BytesIO(message.value()))
             alert = next(reader)  # raise StopIteration
+            assert isinstance(alert, dict)
             stats = topic_stats[message.topic()]
             if alert["candidate"]["jd"] < stats[0]:
                 stats[0] = alert["candidate"]["jd"]

ampel/ztf/t0/load/ZTFAlertArchiverV3.py

@@ -65,6 +65,7 @@ def emit() -> Iterator[bytes]:
             if not alerts:
                 return
             chunk = io.BytesIO()
+            assert schema is not None
             fastavro.writer(chunk, schema, alerts)
             yield chunk.getvalue()
             alerts.clear()