code: function(sessionId) {
          if (_getSession(sessionId) !== null) {
              // The session exists: what about the relative Session Request Handler?
              if (typeof(_sessionRHs[sessionId]) === "undefined") {
                  _sessionRHs[sessionId] = new ghostdriver.SessionReqHand(_getSession(sessionId));
              }
              return _sessionRHs[sessionId];
          }
          return null;
      }
docs: private: