Install bootstraptheme sylius

hello i try to install bootstrap theme for sylius in documentation in the last step need to run yarn encore production and i have this error : Error: Duplicate name “app” passed to addEntry(): entries must be unique.
what i can do for leave this ?

Check the original webpack.config.js (on the project root) and remove that one.
Another approach, would be to rename the theme one to “myTheme”