private function _getLevelAndTargetLoggers( $target )
    {
        $target = strpos($target, ':') !== false ? explode( ':' , $target ) : ['', '*'];
        list($level,$target_loggers) = $target;
        $target_loggers = explode( ',' , $target_loggers );
        $target_loggers = array_map( 'trim', $target_loggers );
        if (in_array('*',$target_loggers))
        {
            $target_loggers = array_keys($this->loggers);
        }
        return array( $level, $target_loggers );
    }