code: function(eventName, fn) {
      if (!fn) {
        delete apos.handlers[eventName];
        return;
      }
      apos.handlers[eventName] = _.filter(apos.handlers[eventName], function(_fn) {
        return fn !== _fn;
      });
    }
docs: Remove an Apostrophe event handler. If fn is not supplied, all handlers for the given eventName are removed.