diff --git a/README.md b/README.md
index 5b102a6..36cb6e3 100644
--- a/README.md
+++ b/README.md
@@ -223,7 +223,7 @@ Possible options:
 - CssMinimizerPlugin.cssnanoMinify
 - CssMinimizerPlugin.cssoMinify
 - CssMinimizerPlugin.cleanCssMinify
-- async (data, inputMap, minimizerOptions) => {return {code: `a{color: red}`, map: `...`, warnings: []}}
+- `async (data, inputMap, minimizerOptions) => {return {code: "a{color: red}", map: "...", warnings: []}}`
 
 > ⚠️ **Always use `require` inside `minify` function when `parallel` option enabled**.