Invalid prop: type check failed for prop "centerXs". Expected Boolean, got String in pug

[iboldurev]

Hi, i have problem

in pug template example:

<template lang="pug"> div container(fluid) row(centerXs=true) </template>

in console

vue.esm.js?65d7:476 [Vue warn]: Invalid prop: type check failed for prop "centerXs". Expected Boolean, got String.

[iboldurev]

Is it correct to fix it just putting the following at the top of the template?

doctype html