1 files changed, 18 insertions, 4 deletions
diff --git a/lib/sqlalchemy/orm/base.py b/lib/sqlalchemy/orm/base.py
index c79592625..31dceb065 100644
--- a/lib/sqlalchemy/orm/base.py
+++ b/lib/sqlalchemy/orm/base.py
@@ -10,11 +10,13 @@
 """
 
 import operator
+import typing
 
 from . import exc
 from .. import exc as sa_exc
 from .. import inspection
 from .. import util
+from ..util import typing as compat_typing
 
 
 PASSIVE_NO_RESULT = util.symbol(
@@ -221,13 +223,25 @@ _DEFER_FOR_STATE = util.symbol("DEFER_FOR_STATE")
 _RAISE_FOR_STATE = util.symbol("RAISE_FOR_STATE")
 
 
-def _assertions(*assertions):
+_Fn = typing.TypeVar("_Fn", bound=typing.Callable)
+_Args = compat_typing.ParamSpec("_Args")
+_Self = typing.TypeVar("_Self")
+
+
+def _assertions(
+    *assertions,
+) -> typing.Callable[
+    [typing.Callable[compat_typing.Concatenate[_Fn, _Args], _Self]],
+    typing.Callable[compat_typing.Concatenate[_Fn, _Args], _Self],
+]:
     @util.decorator
-    def generate(fn, *args, **kw):
-        self = args[0]
+    def generate(
+        fn: _Fn, self: _Self, *args: _Args.args, **kw: _Args.kwargs
+    ) -> _Self:
         for assertion in assertions:
             assertion(self, fn.__name__)
-        fn(self, *args[1:], **kw)
+        fn(self, *args, **kw)
+        return self
 
     return generate