docs: function (k, v) {
          promiseChain = promiseChain.then(function() {
            return self.set(k, v);
          }).catch(function (e) {
            // console.log("Caught error setting {", k, ":", v, "}: ", e);
            self.emit('error', e);
            return Q.fcall(function () {});
          });
        }