diff --git a/python/online/fxreader/pr34/commands_typed/typing.py b/python/online/fxreader/pr34/commands_typed/typing.py
index 66011df..0ca727e 100644
--- a/python/online/fxreader/pr34/commands_typed/typing.py
+++ b/python/online/fxreader/pr34/commands_typed/typing.py
@@ -2,7 +2,7 @@
 # https://gitea.fxreader.online/fxreader.online/freelance-project-34-marketing-blog/issues/2#issue-25
 
 import typing
-from typing import Any
+from typing import Any, TypeVar, Optional, Iterable, Sequence
 from typing_extensions import Protocol
 from abc import abstractmethod
 
@@ -26,3 +26,15 @@ class Comparable(Protocol):
 
 	def __ge__(self: C, other: C) -> bool:
 		return not self < other
+
+T = TypeVar('T', bound='Iterable[Any] | Sequence[Any]')
+
+def check_generic(
+	o: Any,
+	t: type[T]
+) -> T:
+	res = cast(T[Any], o)
+
+	assert isinstance(o, t)
+
+	return res