MD_STD/exceptions/MDFailedToCreateDirectory.php

<?PHP
declare(strict_types = 1);

/**
 * Reports a failure to create a new directory.
 */
final class MDFailedToCreateDirectory extends Exception {
    /**
     * Error message.
     *
     * @return string
     */
    public function errorMessage() {
        //error message
        return 'Failed to create directory';

    }
}