code: function(obj) {
  		var fromObj;
  		for (var i = 1; i < arguments.length; i++) {
  			fromObj = arguments[i];
  			_.forIn(fromObj, function(value, key) {
  				if (value === undefined) {
  					delete obj[key];
  				} else {
  					obj[key] = value;
  				}
  			});
  		}
  
  		return obj;
  	}
docs: extendNoUndef: function(obj [,fromObj] [,fromObj] [,fromObj]) sets all keys from fromObj onto obj, deleting undefined values