TYPO3/Extbase/Session.php
public static function has($key, $type = 'ses')
    {
        return ($GLOBALS['TSFE']->fe_user->getKey(self::isType($type), $key)) ? true : false;
    }
public static function has($key, $type = 'ses')
    {
        return ($GLOBALS['TSFE']->fe_user->getKey(self::isType($type), $key)) ? true : false;
    }
public static function has ( $ key , $ type = 'ses' ) { return ( $ GLOBALS [ 'TSFE' ] -> fe_user -> getKey ( self :: isType ( $ type ) , $ key ) ) ? true : false ; }
Checks whether a key in fe_user session exists

@param string $key
@param string $type - possible values: ses|user
@return boolean
Checks whether a key in fe_user session exists