diff --git a/asynckivy/_n_frames.py b/asynckivy/_n_frames.py
index 3dc3da4..c6aab41 100644
--- a/asynckivy/_n_frames.py
+++ b/asynckivy/_n_frames.py
@@ -19,7 +19,7 @@ def _resume(dt):
 
 
 @types.coroutine
-def one_frame():
+def one_frame(*, _trigger_resume=_trigger_resume):  # default引數を使った最適化を試してみる
     '''(experimental)
     wait for one frame.
 
@@ -37,7 +37,7 @@ async def async_fn():
     yield _waiting.append
 
 
-async def n_frames(n: int):
+async def n_frames(n: int, *, _one_frame=one_frame, _range=range):  # default引數を使った最適化を試してみる
     '''(experimental)
     wait for the specified number of frames.
 
@@ -53,6 +53,5 @@ async def async_fn():
     '''
     if n < 0:
         raise ValueError("Cannot wait for negative number of frames")
-    _one_frame = one_frame
-    for __ in range(n):
+    for __ in _range(n):
         await _one_frame()