diff --git a/epub_reader_framework.install b/epub_reader_framework.install
index 561ffe4e28d38aefc4b857f18f8e81aa3b3688ba..64d7adba3e79587ca7025bf7d55b9a58c6607102 100644
--- a/epub_reader_framework.install
+++ b/epub_reader_framework.install
@@ -9,6 +9,7 @@
  * Implements hook_requirements().
  */
 function epub_reader_framework_requirements($phase) {
+  $requirements = []; 
   if ($phase == 'runtime') {
     /** @var \Drupal\Core\StreamWrapper\StreamWrapperManager $stream_wrapper_manager */
     $stream_wrapper_manager = \Drupal::service('stream_wrapper_manager');