Exactly, `DEFAULT_PROPERTIES` can't be overwritten. They are a constant.

What I wanted to say is that: `@input_properties` will never get new values from `properties` if the key from `DEFAULT_PROPERTIES` matches. `DEFAULT_PROPERTIES` always win, if that is what you wanted. You can't set any property in `properties` that is already present in `DEFAULT_PROPERTIES`. At least it looks quite confusing to me.