useAnimation made optional in Callout

useAnimation should be optional in Callout close and open. I couldn't find any official documentation on this, but SharePoint defaults to false if it is not set:

this.close = function(useAnimation) {
   useAnimation = m$.isBoolean(useAnimation) ? useAnimation : false;

Examples online also shows that this argument should be optional:
http://blog.alexboev.com/2012/08/custom-callouts-in-sharepoint-2013_21.html