is()
is(string $meta,\MatthiasWeb\RealMediaLibrary\api\IFolder $folder,boolean $persist = null): boolean
Gets (and persists) a checkbox to the folder metadata.
Parameters
| string | $meta | The meta key |
| \MatthiasWeb\RealMediaLibrary\api\IFolder | $folder | The folder |
| boolean | $persist | If set it will be updated or deleted |