diff --git a/lib/gruff/patch/rmagick.rb b/lib/gruff/patch/rmagick.rb
index <HASH>..<HASH> 100644
--- a/lib/gruff/patch/rmagick.rb
+++ b/lib/gruff/patch/rmagick.rb
@@ -13,6 +13,7 @@ module Magick
                text.gsub('%', '%%'))
     end
 
+    remove_method :stroke_opacity
     def stroke_opacity(_opacity)
       raise '#stroke_opacity method has different behavior between RMagick and RMagick4J. Should not use this method.'
     end
refactor: Remove stroke_opacity before overriding to get rid of warning message (#<I>)

This patch will remove following warning message.



```

$ bundle exec rake

/opt/gruff/lib/gruff/patch/rmagick.rb:<I>: warning: method redefined; discarding old stroke_opacity

```