diff --git a/lib/command/createbucket.php b/lib/command/createbucket.php
index f773fe85..bc25589b 100644
--- a/lib/command/createbucket.php
+++ b/lib/command/createbucket.php
@@ -59,9 +59,9 @@ protected function configure() {
 	 * @param InputInterface $input
 	 * @param OutputInterface $output
 	 *
-	 * @return int|null|void
+	 * @return int
 	 */
-	protected function execute(InputInterface $input, OutputInterface $output) {
+	protected function execute(InputInterface $input, OutputInterface $output): int {
 		if (!$input->getOption('accept-warning')) {
 			$helper = new QuestionHelper();
 			$q = <<<EOS
@@ -108,6 +108,7 @@ protected function execute(InputInterface $input, OutputInterface $output) {
 				'Status' => 'Enabled',
 				'MFADelete' => 'Disabled']
 		]);
+		return 0;
 	}
 
 	private function getClient() {
diff --git a/lib/command/s3list.php b/lib/command/s3list.php
index 06a9dacd..293ee862 100644
--- a/lib/command/s3list.php
+++ b/lib/command/s3list.php
@@ -55,9 +55,9 @@ protected function configure() {
 	 * @param InputInterface $input
 	 * @param OutputInterface $output
 	 *
-	 * @return int|null|void
+	 * @return int
 	 */
-	protected function execute(InputInterface $input, OutputInterface $output) {
+	protected function execute(InputInterface $input, OutputInterface $output): int {
 		$client = $this->getClient();
 
 		$bucketName = $input->getArgument('bucket');
@@ -100,6 +100,7 @@ protected function execute(InputInterface $input, OutputInterface $output) {
 				$this->printValue($output, $markers, ['Key', 'LastModified', 'VersionId', 'IsLatest']);
 			}
 		}
+		return 0;
 	}
 
 	private function getClient() {