concrete/src/Console/ServiceProvider.php
private function installed()
    {
        if ($this->installed === null) {
            $this->installed = $this->app->isInstalled();
        }

        return $this->installed;
    }
private function installed()
    {
        if ($this->installed === null) {
            $this->installed = $this->app->isInstalled();
        }

        return $this->installed;
    }
private function installed ( ) { if ( $ this -> installed === null ) { $ this -> installed = $ this -> app -> isInstalled ( ) ; } return $ this -> installed ; }
Determine if the app is currently installed

@return bool
Determine if the app is currently installed