diff --git a/README.md b/README.md
index 114eb7b..8e4c995 100644
--- a/README.md
+++ b/README.md
@@ -27,7 +27,7 @@ clock = asyncgui_ext.clock.Clock()
 while running:
     ...
 
-    dt = pygame_clock.advance(fps)
+    dt = pygame_clock.tick(fps)
     clock.advance(dt)
 ```
 
diff --git a/pyproject.toml b/pyproject.toml
index 87b714f..69a05e3 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "asyncgui-ext-clock"
-version = "0.6.1.dev0"
+version = "0.6.1"
 description = "An event scheduler for asyncgui programs"
 authors = ["Nattōsai Mitō <flow4re2c@gmail.com>"]
 license = "MIT"
diff --git a/sphinx/readme_jp.rst b/sphinx/readme_jp.rst
index eeb3304..82d7c58 100644
--- a/sphinx/readme_jp.rst
+++ b/sphinx/readme_jp.rst
@@ -36,7 +36,7 @@ APIに渡す時間の単位は統一さえされていれば何でも構いま
     while running:
         ...
 
-        dt = pygame_clock.advance(fps)
+        dt = pygame_clock.tick(fps)
         clock.advance(dt)
 
 ``Kivy`` を使っているなら以下のようになるでしょう。
diff --git a/src/asyncgui_ext/clock.py b/src/asyncgui_ext/clock.py
index 0114542..eefe82f 100644
--- a/src/asyncgui_ext/clock.py
+++ b/src/asyncgui_ext/clock.py
@@ -44,8 +44,6 @@ def __exit__(self, *__):
 
 
 class Clock:
-    __slots__ = ('_cur_time', '_events', '_events_to_be_added', '__weakref__', )
-
     def __init__(self, initial_time=0):
         self._cur_time = initial_time
         self._events: list[ClockEvent] = []
@@ -90,6 +88,7 @@ def advance(self, delta_time):
         self._events_to_be_added = events
 
     tick = advance
+    '''An alias of :meth:`advance`.'''
 
     def schedule_interval(self, func, interval) -> ClockEvent:
         '''