How to find blocking task and resume it

I am looking to build a workflow to search a “vCloud:Host” for blocked tasks and then resume the tasks. At the moment, I have the “vcloud:host” and blocking event ID as input parameters. The scriptable task has been set up as follows:

var host = vcdHost;
var task = host.getEntityById(VclFinderType.BLOCKING_TASK, eventID);

However, if I print the task, it is null.