如何使用匿名函数删除作为addEventListener的EventListener？

var handler;

function doSomethingWith(param) {
    handler = function(){
        document.write(param);
    };  
    document.body.addEventListener(\'scroll\', handler,false);
}
setTimeout(function() {
     document.body.removeEventListener(\'scroll\', handler ,false);
}, 3000);

var Handler = (function(){
    var i = 1,
        listeners = {};

    return {
        addListener: function(element, event, handler, capture) {
            element.addEventListener(event, handler, capture);
            listeners[i] = {element: element, 
                             event: event, 
                             handler: handler, 
                             capture: capture};
            return i++;
        },
        removeListener: function(id) {
            if(id in listeners) {
                var h = listeners[id];
                h.element.removeEventListener(h.event, h.handler, h.capture);
                delete listeners[id];
            }
        }
    };
}());

function doSomethingWith(param) {
    return Handler.addListener(document.body, \'scroll\', function() {
        document.write(param);
    }, false);
}

var handler = doSomethingWith(\'Test. \');

setTimeout(function() {
     Handler.removeListener(handler);
}, 3000);

function doSomethingWith(param) {
   var fn = function(){ document.write(param); };
   document.body.addEventListener(\'scroll\', fn, false);
   setTimeout(function(){ document.body.removeEventListener(\'scroll\', fn, false); }, 3000);
}
doSomethingWith(\'Test. \');

const ownAddEventListener = (scope, type, handler, capture) => {
  scope.addEventListener(type, handler, capture);
  return () => {
    scope.removeEventListener(type, handler, capture);    
  }
}

// Add event listener
const disposer = ownAddEventListener(document.body, \'scroll\', () => { 
  // do something
}, false);

// Remove event listener
disposer();

[Element].addEventListener(\'click\', () => {...}, {
  capture: false,
  once: true
});