diff --git a/src/Choir/Http/Client/CurlClient.php b/src/Choir/Http/Client/CurlClient.php
index 5c59170..a17a045 100644
--- a/src/Choir/Http/Client/CurlClient.php
+++ b/src/Choir/Http/Client/CurlClient.php
@@ -32,17 +32,11 @@ class CurlClient implements ClientInterface, TimeoutInterface
         $this->curl_options = $curl_options;
     }
 
-    /**
-     * {@inheritDoc}
-     */
     public function setTimeout(int $timeout)
     {
         $this->curl_options[CURLOPT_TIMEOUT_MS] = $timeout;
     }
 
-    /**
-     * {@inheritDoc}
-     */
     public function sendRequest(RequestInterface $request): ResponseInterface
     {
         $handle = $this->createHandle($request);
diff --git a/src/Choir/Http/Client/Exception/ClientException.php b/src/Choir/Http/Client/Exception/ClientException.php
index 081bbcf..7402b6c 100644
--- a/src/Choir/Http/Client/Exception/ClientException.php
+++ b/src/Choir/Http/Client/Exception/ClientException.php
@@ -6,6 +6,4 @@ namespace Choir\Http\Client\Exception;
 
 use Psr\Http\Client\ClientExceptionInterface;
 
-class ClientException extends \Exception implements ClientExceptionInterface
-{
-}
+class ClientException extends \Exception implements ClientExceptionInterface {}
diff --git a/src/Choir/Http/Client/Exception/NetworkException.php b/src/Choir/Http/Client/Exception/NetworkException.php
index 9589943..efbb20c 100644
--- a/src/Choir/Http/Client/Exception/NetworkException.php
+++ b/src/Choir/Http/Client/Exception/NetworkException.php
@@ -11,7 +11,7 @@ class NetworkException extends \Exception implements NetworkExceptionInterface
 {
     private RequestInterface $request;
 
-    public function __construct(RequestInterface $request, $message = '', $code = 0, \Throwable $previous = null)
+    public function __construct(RequestInterface $request, $message = '', $code = 0, ?\Throwable $previous = null)
     {
         $this->request = $request;
         parent::__construct($message, $code, $previous);
diff --git a/src/Choir/Http/Client/Exception/RequestException.php b/src/Choir/Http/Client/Exception/RequestException.php
index d28205c..fffcdf8 100644
--- a/src/Choir/Http/Client/Exception/RequestException.php
+++ b/src/Choir/Http/Client/Exception/RequestException.php
@@ -11,15 +11,12 @@ class RequestException extends \Exception implements RequestExceptionInterface
 {
     private RequestInterface $request;
 
-    public function __construct(RequestInterface $request, $message = '', $code = 0, \Throwable $previous = null)
+    public function __construct(RequestInterface $request, $message = '', $code = 0, ?\Throwable $previous = null)
     {
         $this->request = $request;
         parent::__construct($message, $code, $previous);
     }
 
-    /**
-     * {@inheritDoc}
-     */
     public function getRequest(): RequestInterface
     {
         return $this->request;
diff --git a/src/Choir/Http/Client/StreamClient.php b/src/Choir/Http/Client/StreamClient.php
index 08948bf..2a7a4f3 100644
--- a/src/Choir/Http/Client/StreamClient.php
+++ b/src/Choir/Http/Client/StreamClient.php
@@ -44,7 +44,6 @@ class StreamClient implements TimeoutInterface, ClientInterface
     }
 
     /**
-     * {@inheritdoc}
      * @throws \Exception
      */
     public function sendRequest(RequestInterface $request): ResponseInterface
diff --git a/src/Choir/Http/Stream.php b/src/Choir/Http/Stream.php
index e89805d..900973a 100644
--- a/src/Choir/Http/Stream.php
+++ b/src/Choir/Http/Stream.php
@@ -38,9 +38,7 @@ class Stream implements StreamInterface
 
     private ?int $size = null;
 
-    private function __construct()
-    {
-    }
+    private function __construct() {}
 
     /**
      * Closes the stream when the destructed.
diff --git a/src/Choir/WebSocket/FrameFactory.php b/src/Choir/WebSocket/FrameFactory.php
index 007d6d0..532fa14 100644
--- a/src/Choir/WebSocket/FrameFactory.php
+++ b/src/Choir/WebSocket/FrameFactory.php
@@ -26,7 +26,7 @@ class FrameFactory
         return new Frame($payload, Opcode::BINARY, true, true);
     }
 
-    public static function createCloseFrame(int $code = null, string $reason = null): Frame
+    public static function createCloseFrame(?int $code = null, ?string $reason = null): Frame
     {
         return new CloseFrame($code, $reason);
     }