--- ../src/Imdb/Cache.php
+++ ../src/Imdb/Cache.php
@@ -2,6 +2,7 @@

 namespace Imdb;

+use DateInterval;
 use Psr\Log\LoggerInterface;
 use Psr\SimpleCache\CacheInterface;

@@ -53,7 +54,7 @@
     /**
      * @inheritdoc
      */
-    public function get($key, $default = null)
+    public function get(string $key, mixed $default = null): mixed
     {
         if (!$this->config->usecache) {
             return $default;
@@ -90,7 +91,7 @@
     /**
      * @inheritdoc
      */
-    public function set($key, $value, $ttl = null)
+    public function set(string $key, mixed $value, null|int|DateInterval $ttl = null): bool
     {
         if (!$this->config->storecache) {
             return false;
@@ -150,32 +151,32 @@
     }

     // Some empty functions so we match the interface. These will never be used
-    public function getMultiple($keys, $default = null)
+    public function getMultiple(iterable $keys, mixed $default = null): iterable
     {
         return [];
     }

-    public function clear()
+    public function clear(): bool
     {
         return false;
     }

-    public function delete($key)
+    public function delete(string $key): bool
     {
         return false;
     }

-    public function deleteMultiple($keys)
+    public function deleteMultiple(iterable $keys): bool
     {
         return false;
     }

-    public function has($key)
+    public function has(string $key): bool
     {
         return false;
     }

-    public function setMultiple($values, $ttl = null)
+    public function setMultiple(iterable $values, null|int|\DateInterval $ttl = null): bool
     {
         return false;
     }