docs: function (model, options, callback) {
  
                  var self = this;
  
                  flow()
                      .seq(function (cb) {
                          self._beforeModelSave(model, options, cb);
                      })
                      .seq("result", function (cb) {
                          self._saveModel(model, options, cb);
                      })
                      .seq(function (cb) {
                          self._afterModelSave(this.vars.result || model, options, cb);
                      })
                      .exec(function (err, results) {
                          callback && callback(err, results.result || model, options);
                      });
              }