datum: don't use @OverRide decorator (only availabel from 3.12)

src/pymcnp/files/inp/datum.py

@@ -6,7 +6,7 @@
 """
 
 import re
-from typing import Union, override, Final
+from typing import Union, Final
 from enum import StrEnum
 
 from .card import Card
@@ -1171,8 +1171,8 @@ def __init__(self, volumes: tuple[float], has_no: bool = False):
         self.has_no = has_no
         self.volumes = volumes
 
-    @override
     def to_mcnp(self) -> str:
+        """Overrides the baseclass function."""
         if self.has_no:
             return f"vol no {' '.join(str(volume) for volume in self.volumes)}"
         else: