diff --git a/aioreactive/create.py b/aioreactive/create.py
index 7f6ef60..7d442ec 100644
--- a/aioreactive/create.py
+++ b/aioreactive/create.py
@@ -1,7 +1,7 @@
 import asyncio
 import logging
 from asyncio import Future
-from typing import Any, AsyncIterable, Awaitable, Callable, Iterable, Optional, Tuple, TypeVar
+from typing import Any, AsyncIterable, Awaitable, Callable, Iterable, Optional, Tuple, TypeVar, cast
 
 from expression.core import TailCallResult, aiotools, tailrec_async
 from expression.core.fn import TailCall
@@ -66,7 +66,8 @@ async def worker(obv: AsyncObserver[TSource], _: CancellationToken) -> None:
         finally:
             await obv.aclose()
 
-    return of_async_worker(worker)
+    ret = of_async_worker(worker)
+    return cast(AsyncObservable[TSource], ret)  # NOTE: pyright issue
 
 
 def of_async_iterable(iterable: AsyncIterable[TSource]) -> AsyncObservable[TSource]:
@@ -160,7 +161,8 @@ async def worker(obv: AsyncObserver[TSource], token: CancellationToken) -> None:
 
         await obv.aclose()
 
-    return of_async_worker(worker)
+    ret = of_async_worker(worker)
+    return cast(AsyncObservable[TSource], ret)  # NOTE: pyright issue
 
 
 def defer(factory: Callable[[], AsyncObservable[TSource]]) -> AsyncObservable[TSource]:
diff --git a/aioreactive/msg.py b/aioreactive/msg.py
index a4a3709..708a3aa 100644
--- a/aioreactive/msg.py
+++ b/aioreactive/msg.py
@@ -2,7 +2,7 @@
 """
 from abc import ABC
 from dataclasses import dataclass
-from typing import Any, Iterable, NewType, Type, TypeVar, get_origin
+from typing import Any, Iterable, NewType, TypeVar, get_origin
 
 from expression.core import SupportsMatch
 from expression.system import AsyncDisposable
diff --git a/aioreactive/observers.py b/aioreactive/observers.py
index 09dc610..89be5f0 100644
--- a/aioreactive/observers.py
+++ b/aioreactive/observers.py
@@ -295,7 +295,7 @@ async def aclose(self) -> None:
         self._is_stopped = True
 
         if self._has_value:
-            self.set_result(cast(TSource, self._last_value))
+            self.set_result(cast("TSource", self._last_value))
         else:
             self.cancel()
         await self._aclose()
diff --git a/aioreactive/timeshift.py b/aioreactive/timeshift.py
index ff48c0e..aa0f577 100644
--- a/aioreactive/timeshift.py
+++ b/aioreactive/timeshift.py
@@ -4,7 +4,7 @@
 from typing import Iterable, NoReturn, Tuple, TypeVar
 
 from expression.collections import seq
-from expression.core import MailboxProcessor, TailCall, TailCallResult, aiotools, match, pipe, snd, tailrec_async
+from expression.core import MailboxProcessor, TailCall, TailCallResult, aiotools, match, pipe, fst, tailrec_async
 from expression.system import CancellationTokenSource
 
 from .combine import with_latest_from
@@ -152,8 +152,12 @@ def _sample(source: AsyncObservable[TSource]) -> AsyncObservable[TSource]:
         timer = interval(seconds, seconds)
 
         if seconds > 0:
-            return pipe(source, with_latest_from(timer), map(snd))
-        else:
-            return source
+            return pipe(
+                source,
+                with_latest_from(timer),
+                map(fst),
+            )
+
+        return source
 
     return _sample
diff --git a/aioreactive/transform.py b/aioreactive/transform.py
index a75a602..31333b8 100644
--- a/aioreactive/transform.py
+++ b/aioreactive/transform.py
@@ -69,7 +69,7 @@ def starmap_async(mapper: Callable[[TSource, int], Awaitable[TResult]]) -> Strea
     ...
 
 
-def starmap_async(amapper: Callable[..., Awaitable[Any]]) -> Stream[TSource, Any]:
+def starmap_async(amapper: Callable[..., Awaitable[TResult]]) -> Stream[Tuple[TSource, ...], TResult]:
     """Map async spreading arguments to the async mapper.
 
     Returns an observable sequence whose elements are the result of
@@ -96,11 +96,11 @@ def handler(next: Callable[[TResult], Awaitable[None]], x: TSource) -> Awaitable
 
 
 @overload
-def starmap(mapper: Callable[[TSource, int], TResult]) -> Stream[TSource, TResult]:
+def starmap(mapper: Callable[[TSource, int], TResult]) -> Stream[Tuple[TSource, int], TResult]:
     ...
 
 
-def starmap(mapper: Callable[..., Any]) -> Stream[TSource, Any]:
+def starmap(mapper: Callable[..., TResult]) -> Stream[Tuple[TSource, ...], TResult]:
     """Map and spread the arguments to the mapper.
 
     Returns an observable sequence whose elements are the result of
@@ -291,8 +291,12 @@ async def message_loop(
 
         inner_agent = MailboxProcessor.start(worker)
 
-        async def asend(xs: TSource) -> None:
-            pipe(xs, InnerObservableMsg, inner_agent.post)
+        async def asend(xs: AsyncObservable[TSource]) -> None:
+            pipe(
+                xs,
+                InnerObservableMsg,
+                inner_agent.post,
+            )
 
         async def athrow(error: Exception) -> None:
             await safe_obv.athrow(error)
diff --git a/examples/timeflies/timeflies.py b/examples/timeflies/timeflies.py
index 9367dfb..9e92b5c 100644
--- a/examples/timeflies/timeflies.py
+++ b/examples/timeflies/timeflies.py
@@ -1,5 +1,4 @@
 import asyncio
-import logging
 import signal
 import sys
 from tkinter import Event, Frame, Label, Misc, Tk