Define Constraint to be Hashable as well

For LRU cache.
gaphor · Jul 9, 2021 · 99d90ac · 99d90ac
1 parent 5f9f717
commit 99d90ac
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/gaphas/solver/constraint.py b/gaphas/solver/constraint.py
@@ -1,14 +1,14 @@
 from __future__ import annotations
 
-from typing import Callable, Collection, Set
+from typing import Callable, Collection, Hashable, Set
 
 from typing_extensions import Protocol, runtime_checkable
 
 from gaphas.solver.variable import Variable
 
 
 @runtime_checkable
-class Constraint(Protocol):
+class Constraint(Protocol, Hashable):
     def add_handler(self, handler: Callable[[Constraint], None]) -> None:
         ...