Fix #1038 and #1039 (#1040)

Resolves #1038 and #1039

lhotse/audio.py

@@ -957,7 +957,7 @@ class RecordingSet(Serializable, AlgorithmMixin):
             >>> recs_24k = recs.resample(24000)
     """
 
-    def __init__(self, recordings: Mapping[str, Recording] = None) -> None:
+    def __init__(self, recordings: Optional[Mapping[str, Recording]] = None) -> None:
         self.recordings = ifnone(recordings, {})
 
     def __eq__(self, other: "RecordingSet") -> bool:

lhotse/features/base.py

@@ -598,7 +598,7 @@ class FeatureSet(Serializable, AlgorithmMixin):
     When a given recording/time-range/channel is unavailable, raises a KeyError.
     """
 
-    def __init__(self, features: List[Features] = None) -> None:
+    def __init__(self, features: Optional[List[Features]] = None) -> None:
         self.features = ifnone(features, [])
 
     def __eq__(self, other: "FeatureSet") -> bool:

lhotse/serialization.py

@@ -213,6 +213,7 @@ def _maybe_open(self):
     def close(self):
         if self.file is not None:
             self.file.close()
+            self.file = None
 
     def contains(self, item: Union[str, Any]) -> bool:
         return item in self
@@ -246,7 +247,7 @@ def open_manifest(self) -> Optional[Manifest]:
         """
         if not Path(self.path).exists():
             return None
-        if not self.file.closed:
+        if self.file is not None and not self.file.closed:
             # If the user hasn't finished writing, make sure the latest
             # changes are propagated.
             self.file.flush()

lhotse/supervision.py

@@ -539,7 +539,9 @@ class SupervisionSet(Serializable, AlgorithmMixin):
             >>> shuffled = sups.shuffle()
     """
 
-    def __init__(self, segments: Mapping[str, SupervisionSegment]) -> None:
+    def __init__(
+        self, segments: Optional[Mapping[str, SupervisionSegment]] = None
+    ) -> None:
         self.segments = ifnone(segments, {})
 
     def __eq__(self, other: "SupervisionSet") -> bool: