code: function(sessionId, withUser, callback) {
  
              if (arguments[1] instanceof Function) {
                  callback = withUser;
                  withUser = true;
              }
  
              if (!sessionId) {
                  callback && callback("No sessionId");
                  return;
              }
  
              var api = this.$.api,
                  self = this,
                  session = api.createEntity(Session, sessionId);
  
              session.fetch({
                  fetchSubModels: (withUser ? ["user"] : []),
                  noCache: true
              }, function(err, session) {
  
                  if (err) {
                      session = null;
                  }
  
                  api.set("session", session);
                  self.set("session", session);
  
                  callback && callback(err, session);
              });
  
          }
docs: *
  
  @param sessionId
  @param [withUser=true]
  @param callback