rem: keys[i] = NullKey; 
add: this.keys[i] = NullKey; 
context:     this.remove = function (key){      for (var i=0;i<keys.length;i++){        var entry = keys[i];        if (entry instanceof NullKey) continue;        if (entry.key == key){            keys[i] = NullKey;        }      }            };
meta: 2141	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/2141/1262bdbcf021afe53e2127f4792d5bb0f6115094/log4js.js/buggy/src/js/log4js.js