Freeze attributes for Repositories

src/sakia/data/repositories/identities.py

@@ -2,7 +2,7 @@ import attr
 from ..entities import Identity
 
 
-@attr.s
+@attr.s(frozen=True)
 class IdentitiesRepo:
     """The repository for Identities entities.
     """

src/sakia/data/repositories/meta.py

 import attr
-from ..entities import Identity
 
 
 @attr.s(frozen=True)