mark Term subclasses as final

Author: Deric-W

lambda_calculus/terms/__init__.py

@@ -6,7 +6,7 @@
 from abc import abstractmethod
 from collections.abc import Sequence, Set, Iterable, Iterator
 from dataclasses import dataclass
-from typing import TypeVar
+from typing import TypeVar, final
 from .. import visitors
 from ..errors import CollisionError
 from ..visitors import walking
@@ -128,6 +128,7 @@ def is_combinator(self) -> bool:
         return not self.free_variables()
 
 
+@final
 @dataclass(unsafe_hash=True, slots=True)
 class Variable(Term[V]):
     """
@@ -197,6 +198,7 @@ def accept(self, visitor: visitors.Visitor[T, V]) -> T:
         return visitor.visit_variable(self)
 
 
+@final
 @dataclass(unsafe_hash=True, slots=True)
 class Abstraction(Term[V]):
     """
@@ -316,6 +318,7 @@ def replace(self, *, bound: V | None = None, body: Term[V] | None = None) -> Abs
         )
 
 
+@final
 @dataclass(unsafe_hash=True, slots=True)
 class Application(Term[V]):
     """