code: function(cb) {
                t.getClassInfo(classes[classIndex++], (err, dbClassInfo) => {
                  if (dbClassInfo) {
                    var deps = dbClassInfo.dependsOn;
                    for (var depName in deps) {
                      t._addRequiredClass(depName);
                    }
                  }
                  if (err && err.code === "ENOCLASSFILE") {
                    console.error(err.message);
                    err = null;
                  }
                  return cb(err);
                });
              }
docs: /* Do