Underscore.js mixing to remove one or more keys from an object

_.remove.js

// remove key from object
_.mixin({
    remove: function(obj, keys){
        return _.chain([keys]).flatten().reduce(function(obj, key){
            delete obj[key];
            return obj;
        }, obj).value();
    }
});

_.remove.js.coffee

# remove key(s) from object
_.mixin
    remove: (obj, keys) ->
        _.chain([keys]).flatten().reduce(
            (obj, key) ->
                delete obj[key]; obj
            , obj).value()