diff --git a/RabbitMq/Producer.php b/RabbitMq/Producer.php
index 446bb611..34bd66af 100644
--- a/RabbitMq/Producer.php
+++ b/RabbitMq/Producer.php
@@ -13,6 +13,12 @@ class Producer extends BaseAmqp implements ProducerInterface
     protected $contentType = 'text/plain';
     protected $deliveryMode = 2;
 
+    /**
+     * Set content type
+     *
+     * @param string $contentType
+     * @return self
+     */
     public function setContentType($contentType)
     {
         $this->contentType = $contentType;
@@ -20,6 +26,12 @@ public function setContentType($contentType)
         return $this;
     }
 
+    /**
+     * Set delivery mode
+     *
+     * @param string $deliveryMode
+     * @return self
+     */
     public function setDeliveryMode($deliveryMode)
     {
         $this->deliveryMode = $deliveryMode;
@@ -46,7 +58,7 @@ public function publish($msgBody, $routingKey = '', $additionalProperties = arra
             $this->setupFabric();
         }
 
-        $msg = new AMQPMessage((string) $msgBody, array_merge($this->getBasicProperties(), $additionalProperties));
+        $msg = new AMQPMessage((string)$msgBody, array_merge($this->getBasicProperties(), $additionalProperties));
 
         if (!empty($headers)) {
             $headersTable = new AMQPTable($headers);
diff --git a/RabbitMq/ProducerInterface.php b/RabbitMq/ProducerInterface.php
index b4e166c1..5e38a8c5 100644
--- a/RabbitMq/ProducerInterface.php
+++ b/RabbitMq/ProducerInterface.php
@@ -5,11 +5,28 @@
 interface ProducerInterface
 {
     /**
-     * Publish a message
+     * Set content type
+     *
+     * @param string $contentType
+     * @return self
+     */
+    public function setContentType($contentType);
+
+    /**
+     * Set delivery mode
+     *
+     * @param string $deliveryMode
+     * @return self
+     */
+    public function setDeliveryMode($deliveryMode);
+
+    /**
+     * Publishes the message and merges additional properties with basic properties
      *
      * @param string $msgBody
      * @param string $routingKey
      * @param array $additionalProperties
+     * @param array $headers
      */
-    public function publish($msgBody, $routingKey = '', $additionalProperties = array());
+    public function publish($msgBody, $routingKey = '', $additionalProperties = array(), array $headers = null);
 }