Update dependency pylint to ==3.3.7,<3.4.0

requirements/dev.txt

@@ -1,7 +1,7 @@
 black~=25.1.0
 isort==5.13.2
 mypy~=1.15.0
-pylint==3.3.6,<3.4.0
+pylint==3.3.7,<3.4.0
 pytest-cov~=6.1.0
 pytest~=8.3.2
 tox==4.25.0

src/pyrmv/classes/message.py

@@ -81,8 +81,10 @@ class Message:
                 f"{data['validToDate']} {data['validToTime']}", "%Y-%m-%d %H:%M:%S"
             )
         )
-        self.date_start_alt: str = data["altStart"]
+        self.date_start_alt: Union[str, None] = (
-        self.date_end_alt: str = data["altEnd"]
+            None if "altStart" not in data else data["altStart"]
+        )
+        self.date_end_alt: Union[str, None] = None if "altEnd" not in data else data["altEnd"]
         self.time_modified: Union[datetime, None] = (
             None
             if "modDate" not in data or "modTime" not in data