diff --git a/.gitignore b/.gitignore
index da6bcd7..f363432 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,7 @@
 /.idea
 /.*.cache
 /.env.local
+/build
 /composer.lock
 /tmp
 /vendor
diff --git a/src/Akismet.php b/src/Akismet.php
index bd762db..5c509aa 100644
--- a/src/Akismet.php
+++ b/src/Akismet.php
@@ -33,18 +33,18 @@ class Akismet implements LoggerAwareInterface
     private ?string $instance;
     private bool $isTesting;
 
-    public function __construct(HttpClientInterface $client, string $apiKey = null, string $instance = null, bool $isTesting = false)
+    public function __construct(HttpClientInterface $client, ?string $apiKey = null, ?string $instance = null, bool $isTesting = false)
     {
         $this->apiKey = $apiKey;
         $this->instance = $instance;
         $this->isTesting = $isTesting;
 
         $this->client = $client->withOptions([
-           'base_uri' => self::API_BASE_URI,
+            'base_uri' => self::API_BASE_URI,
         ]);
     }
 
-    public function activity(string $month = null, string $order = null, int $limit = null, int $offset = 0): ActivityResponse
+    public function activity(?string $month = null, ?string $order = null, ?int $limit = null, int $offset = 0): ActivityResponse
     {
         if (null !== $month && !preg_match('#^2[0-1][0-9]{2}\-[0-1][0-9]$#', $month)) {
             throw new \RuntimeException('Month must be null or in the format YYYY-MM');
diff --git a/src/AkismetMessage.php b/src/AkismetMessage.php
index 7cc43bf..856e342 100644
--- a/src/AkismetMessage.php
+++ b/src/AkismetMessage.php
@@ -166,11 +166,21 @@ public function getType(): ?MessageType
         return MessageType::tryFrom($this->get('comment_type') ?? '');
     }
 
+    public function getTypeAsString(): ?string
+    {
+        return $this->get('comment_type');
+    }
+
     public function setType(?MessageType $type): static
     {
         return $this->set('comment_type', $type?->value);
     }
 
+    public function setTypeAsString(?string $type): static
+    {
+        return $this->set('comment_type', $type);
+    }
+
     public function getUserAgent(): ?string
     {
         return $this->get('user_agent');
diff --git a/tests/AkismetTest.php b/tests/AkismetTest.php
index 607040c..e500d1c 100644
--- a/tests/AkismetTest.php
+++ b/tests/AkismetTest.php
@@ -90,6 +90,7 @@ public function testMessageAccessors(): void
         $this->assertSame('edit', $message->getRecheckReason());
         $this->assertSame('https://www.google.com', $message->getReferrer());
         $this->assertSame(MessageType::BLOG_POST, $message->getType());
+        $this->assertSame(MessageType::BLOG_POST->value, $message->getTypeAsString());
         $this->assertSame('Custom Browser 684', $message->getUserAgent());
         $this->assertSame('guest', $message->getUserRole());
         $this->assertSame('12.34.56.78', $message->getUserIP());
@@ -106,6 +107,9 @@ public function testMessageAccessors(): void
 
         $message->setReferrer(null);
         $this->assertNull($message->getReferrer());
+
+        $message->setTypeAsString('foo');
+        $this->assertSame('foo', $message->getTypeAsString());
     }
 
     public function testPSR7Integration(): void