Using aesop_center

How can I use [aesop_center] in my posts? I tried to use it with an iFrame but it did not work. What I miss here:
[aesop_center <iframe width='100%' height='500px' frameBorder='0' src='http://a.tiles.mapbox.com/v3/sourena.map-70oklwyj/attribution,zoompan,zoomwheel,geocoder,share.html'></iframe>]

https://ww.wp.xz.cn/plugins/aesop-story-engine/