diff --git a/pittgoogle/alert.py b/pittgoogle/alert.py
index 2ef2cde..95ebae8 100644
--- a/pittgoogle/alert.py
+++ b/pittgoogle/alert.py
@@ -49,16 +49,16 @@ class Alert:
             `Alert` may not be available. See :meth:`pittgoogle.Schemas.names` for a list of options.
     """
 
-    msg: Optional[
-        Union["google.cloud.pubsub_v1.types.PubsubMessage", types_.PubsubMessageLike]
-    ] = field(default=None)
+    msg: Union["google.cloud.pubsub_v1.types.PubsubMessage", types_.PubsubMessageLike, None] = (
+        field(default=None)
+    )
     """Incoming Pub/Sub message object."""
-    _attributes: Optional[Mapping[str, str]] = field(default=None)
-    _dict: dict | None = field(default=None)
-    _dataframe: Optional["pd.DataFrame"] = field(default=None)
-    schema_name: Optional[str] = field(default=None)
-    _schema: Optional[types_.Schema] = field(default=None, init=False)
-    path: Optional[Path] = field(default=None)
+    _attributes: Mapping[str, str] | None = field(default=None)
+    _dict: Mapping | None = field(default=None)
+    _dataframe: "pd.DataFrame" | None = field(default=None)
+    schema_name: str | None = field(default=None)
+    _schema: types_.Schema | None = field(default=None, init=False)
+    path: Path | None = field(default=None)
 
     # ---- class methods ---- #
     @classmethod