Pass variable to included layout via xml

I want to include a simple layout and pass a static variable to it (string resource here). I followed multiple examples with no luck.

main_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <data></data>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <include android:id="@+id/first_included" layout="@layout/included" app:theValue="@string/firstValue" />
        <include android:id="@+id/first_included" layout="@layout/included" app:theValue="@string/secondValue" />
    </LinearLayout>
</layout>

included.xml

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">
    <data>
        <variable name="theValue" type="String" />
    </data>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@{theValue}"/>    
</layout>

This gives me the compile error

Error: No resource identifier found for attribute 'theValue' in package 'com.just.example'

I do use databinding in the rest of the project and everything works fine. I could set the value programmatically but this one is static, I want to be able to set it in the layout file.