diff --git a/tool/sync_default_gems.rb b/tool/sync_default_gems.rb
index 2ac66f9195..ec70b86752 100755
--- a/tool/sync_default_gems.rb
+++ b/tool/sync_default_gems.rb
@@ -81,7 +81,7 @@ module SyncDefaultGems
     yaml: "ruby/yaml",
     yarp: ["ruby/yarp", "main"],
     zlib: 'ruby/zlib',
-  }.transform_keys {|k| k.to_s}
+  }.transform_keys(&:to_s)
 
   CLASSICAL_DEFAULT_BRANCH = "master"