diff --git a/lib/OpenPayU/Configuration.php b/lib/OpenPayU/Configuration.php
index 539878f..43ad73f 100644
--- a/lib/OpenPayU/Configuration.php
+++ b/lib/OpenPayU/Configuration.php
@@ -97,7 +97,7 @@ public static function getApiVersion()
     }
 
     /**
-     * @param string
+     * @param string $value
      * @throws OpenPayU_Exception_Configuration
      */
     public static function setHashAlgorithm($value)
@@ -172,7 +172,7 @@ public static function getEnvironment()
     }
 
     /**
-     * @param string
+     * @param string $value
      */
     public static function setMerchantPosId($value)
     {
@@ -188,7 +188,7 @@ public static function getMerchantPosId()
     }
 
     /**
-     * @param string
+     * @param string $value
      */
     public static function setSignatureKey($value)
     {
diff --git a/lib/OpenPayU/HttpCurl.php b/lib/OpenPayU/HttpCurl.php
index bb5df70..86f50e5 100644
--- a/lib/OpenPayU/HttpCurl.php
+++ b/lib/OpenPayU/HttpCurl.php
@@ -14,7 +14,7 @@
 class OpenPayU_HttpCurl
 {
     /**
-     * @var
+     * @var array
      */
     static $headers;
 
diff --git a/lib/OpenPayU/Oauth/Cache/OauthCacheFile.php b/lib/OpenPayU/Oauth/Cache/OauthCacheFile.php
index 2042569..87fc2da 100644
--- a/lib/OpenPayU/Oauth/Cache/OauthCacheFile.php
+++ b/lib/OpenPayU/Oauth/Cache/OauthCacheFile.php
@@ -7,7 +7,7 @@ class OauthCacheFile implements OauthCacheInterface
     /**
      * @throws OpenPayU_Exception_Configuration
      */
-    public function __construct(string $directory = null)
+    public function __construct(?string $directory = null)
     {
         if ($directory === null) {
             $directory = __DIR__ . '/../../../Cache';
diff --git a/lib/OpenPayU/Result.php b/lib/OpenPayU/Result.php
index 8272663..c9a8d8e 100644
--- a/lib/OpenPayU/Result.php
+++ b/lib/OpenPayU/Result.php
@@ -201,7 +201,7 @@ public function set($name, $value)
     public function __get($name)
     {
         if (isset($this->{$name}))
-            return $this->name;
+            return $this->{$name};
 
         return null;
     }