diff --git a/src/AzureBlobStorageAdapter.php b/src/AzureBlobStorageAdapter.php
index c9c578a..87aa9c7 100644
--- a/src/AzureBlobStorageAdapter.php
+++ b/src/AzureBlobStorageAdapter.php
@@ -4,8 +4,8 @@
 
 use Illuminate\Support\Arr;
 use League\Flysystem\AzureBlobStorage\AzureBlobStorageAdapter as BaseAzureBlobStorageAdapter;
-use MicrosoftAzure\Storage\Blob\BlobRestProxy;
 use Matthewbdaly\LaravelAzureStorage\Exceptions\InvalidCustomUrl;
+use MicrosoftAzure\Storage\Blob\BlobRestProxy;
 use MicrosoftAzure\Storage\Blob\BlobSharedAccessSignatureHelper;
 use MicrosoftAzure\Storage\Common\Internal\Resources;
 
@@ -33,14 +33,14 @@ final class AzureBlobStorageAdapter extends BaseAzureBlobStorageAdapter
     /**
      * Custom url for getUrl()
      *
-     * @var string
+     * @var string|null
      */
     private $url;
 
     /**
      * The account key to access the storage
      *
-     * @var string
+     * @var string|null
      */
     private $key;
 
@@ -71,6 +71,7 @@ public function __construct(BlobRestProxy $client, string $container, string $ke
      * Get the file URL by given path.
      *
      * @param  string $path Path.
+     *
      * @return string
      */
     public function getUrl(string $path)
@@ -87,6 +88,7 @@ public function getUrl(string $path)
      * @param string $path
      * @param \Datetime|string $ttl
      * @param array $options
+     *
      * @return string
      */
     public function getTemporaryUrl(string $path, $ttl, array $options = [])
diff --git a/src/AzureStorageServiceProvider.php b/src/AzureStorageServiceProvider.php
index 57bf72e..45eac00 100644
--- a/src/AzureStorageServiceProvider.php
+++ b/src/AzureStorageServiceProvider.php
@@ -7,9 +7,10 @@
 use Illuminate\Support\Arr;
 use Illuminate\Support\Facades\Storage;
 use Illuminate\Support\ServiceProvider;
-use League\Flysystem\Filesystem;
+use League\Flysystem\Cached\CacheInterface;
 use League\Flysystem\Cached\CachedAdapter;
 use League\Flysystem\Cached\Storage\Memory as MemoryStore;
+use League\Flysystem\Filesystem;
 use Matthewbdaly\LaravelAzureStorage\Exceptions\CacheAdapterNotInstalled;
 use MicrosoftAzure\Storage\Blob\BlobRestProxy;
 use MicrosoftAzure\Storage\Common\Middlewares\RetryMiddleware;
@@ -94,11 +95,12 @@ public function register()
      * Create a cache store instance.
      *
      * @param  mixed  $config
+     *
      * @return \League\Flysystem\Cached\CacheInterface
      *
      * @throws \InvalidArgumentException
      */
-    protected function createCacheStore($config)
+    protected function createCacheStore($config): CacheInterface
     {
         if ($config === true) {
             return new MemoryStore();
@@ -115,9 +117,10 @@ protected function createCacheStore($config)
      * Create retry middleware instance.
      *
      * @param  array $config
+     *
      * @return RetryMiddleware
      */
-    protected function createRetryMiddleware($config)
+    protected function createRetryMiddleware(array $config): RetryMiddleware
     {
         return RetryMiddlewareFactory::create(
             RetryMiddlewareFactory::GENERAL_RETRY_TYPE,