docs: function (mode, opts, cb) {
              if (isFunction(opts)) {
                  cb = opts;
                  opts = null;
              } else {
                  opts = opts || {};
              }
              if (isFunction(cb)) {
                  var self = this;
                  return this.db.transaction(opts, function () {
                      return self.lock(mode, opts)
                          .chain(function () {
                              return cb.call(self);
                          });
                  });
              } else {
                  return this.db.execute(format(this._static.LOCK, [this._sourceList(this.__opts.from), mode]), opts);
              }
          }