问我无法安装silverstripe 4

EN

Setting up /home/devsquala/public_html/index.php
Setting up /home/devsquala/public_html/mysite/_config.php
Setting up /home/devsquala/public_html/mysite/_config/theme.yml
Setting up /home/devsquala/public_html/.env
Setting up /home/devsquala/public_html/.htaccess
Building database schema...

Parse error: syntax error, unexpected ':', expecting ';' or '{' in /home/devsquala/public_html/vendor/symfony/filesystem/Filesystem.php on line 727
ERROR [Warning]: syntax error, unexpected ':', expecting ';' or '{' IN POST /~devsquala/install.php Line 727 in /home/devsquala/public_html/vendor/symfony/filesystem/Filesystem.php Source ====== 718: if (!is_writable($dir)) { 719: throw new IOException(sprintf('Unable to write to the "%s" directory.', $dir), 0, null, $dir); 720: } 721: 722: if (false === @file_put_contents($filename, $content, FILE_APPEND)) { 723: throw new IOException(sprintf('Failed to write file "%s".', $filename), 0, null, $filename); 724: } 725: } 726: * 727: private function toIterable($files): iterable 728: { 729: return is_array($files) || $files instanceof \Traversable ? $files : array($files); 730: } 731: 732: /** 733: * Gets a 2-tuple of scheme (may be null) and hierarchical part of a filename (e.g. file:///tmp -> array(file, tmp)). Trace ===== SilverStripe\Dev\CliDebugView->renderTrace() DetailedErrorFormatter.php:117 SilverStripe\Logging\DetailedErrorFormatter->output(4, syntax error, unexpected ':', expecting ';' or '{', /home/devsquala/public_html/vendor/symfony/filesystem/Filesystem.php, 727, ) DetailedErrorFormatter.php:53 SilverStripe\Logging\DetailedErrorFormatter->format(Array) AbstractProcessingHandler.php:35 Monolog\Handler\AbstractProcessingHandler->handle(Array) Logger.php:337 Monolog\Logger->addRecord(550, Fatal Error (E_PARSE): syntax error, unexpected ':', expecting ';' or '{', Array) Logger.php:518 Monolog\Logger->log(alert, Fatal Error (E_PARSE): syntax error, unexpected ':', expecting ';' or '{', Array) ErrorHandler.php:181 Monolog\ErrorHandler->handleFatalError()