Fix new mypy error

Author: Rud356

config_framework/utils/loader_specific_deserializer.py

@@ -29,11 +29,11 @@ def __init__(self, deserializers: Dict[
 
     def __call__(
         self,
-        variable: Variable,
+        variable: Variable[Var],
         from_value: Any,
     ) -> Var:
         """
-        Casts value to specific loaders type so it can be saved.
+        Casts value to specific loaders type, so it can be saved.
 
         :param from_value: raw value from loader.
         :returns: validated and caster to python type value.