diff --git a/src/ElixForms/ElixFormsClient.php b/src/ElixForms/ElixFormsClient.php
index b741032..83d7d21 100644
--- a/src/ElixForms/ElixFormsClient.php
+++ b/src/ElixForms/ElixFormsClient.php
@@ -11,7 +11,7 @@ class ElixFormsClient
     private string $baseUrl;
     private Client $httpClient;
 
-    public function __construct(string $baseUrl, Client $httpClient = null)
+    public function __construct(string $baseUrl, ?Client $httpClient)
     {
         $this->baseUrl = rtrim($baseUrl, '/');
         $this->httpClient = $httpClient ?? new Client(['timeout' => 10.0, 'http_errors' => false]);
@@ -22,7 +22,7 @@ class ElixFormsClient
         return new AuthClient($this->baseUrl, $this->httpClient);
     }
 
-    public function request(string $method, string $path, ?array $body = null, array $headers = []): array
+    public function request(string $method, string $path, ?array $body, array $headers = []): array
     {
         $url = $this->baseUrl . '/' . ltrim($path, '/');
         $options = ['headers' => $headers];