return this.slice(0, this.length - 1) + String.fromCharCode(this.charCodeAt(this.length - 1) + 1); 
return this + 1; 
  succ: function() {    return this.slice(0, this.length - 1) +      String.fromCharCode(this.charCodeAt(this.length - 1) + 1);  },
4053	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/4053/37a06e5ed1bdb861348bb0cfd02f71470a0dfdfb/prototype.js/clean/lib/prototype.js