diff --git a/django_fsm/__init__.py b/django_fsm/__init__.py
index c84a9da..43a08ef 100644
--- a/django_fsm/__init__.py
+++ b/django_fsm/__init__.py
@@ -44,8 +44,8 @@
 
     _Model = models.Model
     _Field = models.Field[Any, Any]
-    CharField = models.CharField[str, str]
-    IntegerField = models.IntegerField[int, int]
+    CharField = models.CharField[Any, Any]
+    IntegerField = models.IntegerField[Any, Any]
     ForeignKey = models.ForeignKey[Any, Any]
 
     _StateValue = str | int
@@ -168,10 +168,10 @@ def get_transition(self, source: str) -> Transition | None:
 
     def add_transition(
         self,
-        method: Callable[..., str | int | None],
+        method: Callable[..., _StateValue | Any],
         source: str,
-        target: str | int,
-        on_error: str | int | None = None,
+        target: _StateValue,
+        on_error: _StateValue | None = None,
         conditions: list[Callable[[_Instance], bool]] = [],
         permission: str | Callable[[_Instance, UserWithPermissions], bool] | None = None,
         custom: dict[str, _StrOrPromise] = {},
@@ -225,7 +225,7 @@ def has_transition_perm(self, instance: _Instance, state: str, user: UserWithPer
         else:
             return bool(transition.has_perm(instance, user))
 
-    def next_state(self, current_state: str) -> str | int:
+    def next_state(self, current_state: str) -> _StateValue:
         transition = self.get_transition(current_state)
 
         if transition is None:
@@ -233,7 +233,7 @@ def next_state(self, current_state: str) -> str | int:
 
         return transition.target
 
-    def exception_state(self, current_state: str) -> str | int | None:
+    def exception_state(self, current_state: str) -> _StateValue | None:
         transition = self.get_transition(current_state)
 
         if transition is None:
@@ -534,9 +534,9 @@ def save(self, *args: Any, **kwargs: Any) -> None:
 
 def transition(
     field: FSMFieldMixin,
-    source: str | int | Sequence[str | int] = "*",
-    target: str | int | State | None = None,
-    on_error: str | int | None = None,
+    source: _StateValue | Sequence[_StateValue] = "*",
+    target: _StateValue | State | None = None,
+    on_error: _StateValue | None = None,
     conditions: list[Callable[[Any], bool]] = [],
     permission: str | Callable[[models.Model, UserWithPermissions], bool] | None = None,
     custom: dict[str, _StrOrPromise] = {},
@@ -614,7 +614,7 @@ def get_state(self, model: _Model, transition: Transition, result: Any, args: An
 
 
 class RETURN_VALUE(State):
-    def __init__(self, *allowed_states: Sequence[str | int]) -> None:
+    def __init__(self, *allowed_states: Sequence[_StateValue]) -> None:
         self.allowed_states = allowed_states if allowed_states else None
 
     def get_state(self, model: _Model, transition: Transition, result: Any, args: Any = [], kwargs: Any = {}) -> _ToDo:
@@ -625,7 +625,7 @@ def get_state(self, model: _Model, transition: Transition, result: Any, args: An
 
 
 class GET_STATE(State):
-    def __init__(self, func: Callable[..., str | int], states: Sequence[str | int] | None = None) -> None:
+    def __init__(self, func: Callable[..., _StateValue | Any], states: Sequence[_StateValue] | None = None) -> None:
         self.func = func
         self.allowed_states = states