diff --git a/README.md b/README.md
index 3527c09..bc420fd 100644
--- a/README.md
+++ b/README.md
@@ -63,7 +63,9 @@ require "tartrazine"
 
 lexer = Tartrazine.lexer("crystal")
 theme = Tartrazine.theme("catppuccin-macchiato")
-puts Tartrazine::Html.new.format(File.read(ARGV[0]), lexer, theme)
+formatter = Tartrazine::Html.new
+formatter.theme = theme
+puts formatter.format(File.read(ARGV[0]), lexer)
 ```
 
 ## Contributing
@@ -76,4 +78,4 @@ puts Tartrazine::Html.new.format(File.read(ARGV[0]), lexer, theme)
 
 ## Contributors
 
-- [Roberto Alsina](https://github.com/ralsina) - creator and maintainer
\ No newline at end of file
+- [Roberto Alsina](https://github.com/ralsina) - creator and maintainer