diff --git a/lib/Newsletter/Renderer/Renderer.php b/lib/Newsletter/Renderer/Renderer.php
index 3129eacc90..9c7d9d394e 100644
--- a/lib/Newsletter/Renderer/Renderer.php
+++ b/lib/Newsletter/Renderer/Renderer.php
@@ -167,7 +167,7 @@ class Renderer {
    * @return DomNode
    */
   private function inlineCSSStyles($template) {
-    return $this->CSS_inliner->inlineCSS(null, $template);
+    return $this->CSS_inliner->inlineCSS($template);
   }
 
   /**
diff --git a/lib/Util/CSS.php b/lib/Util/CSS.php
index 80e5aded45..80549c0dfa 100644
--- a/lib/Util/CSS.php
+++ b/lib/Util/CSS.php
@@ -32,15 +32,11 @@ use MailPoet\Newsletter\Renderer\EscapeHelper as EHelper;
 */
 
 class CSS {
-  /*
-  * The core of the algorithm, takes a URL and returns the HTML found there with the CSS inlined.
-  * If you pass $contents then the original HTML is not downloaded and $contents is used instead.
-  * $url is mandatory as it is used to resolve the links to the stylesheets found in the HTML.
-  */
   /**
+   * @param string $contents
    * @return DomNode
    */
-  function inlineCSS($url, $contents = null) {
+  function inlineCSS($contents) {
     $html = pQuery::parseStr($contents);
 
     if (!$html instanceof DomNode) {
diff --git a/tests/unit/Util/CSSTest.php b/tests/unit/Util/CSSTest.php
index b08801535d..b9d807c960 100644
--- a/tests/unit/Util/CSSTest.php
+++ b/tests/unit/Util/CSSTest.php
@@ -41,7 +41,7 @@ class CSSTest extends \MailPoetUnitTest {
     $styles = 'p { color: red; }';
     $content = '<p>Foo</p>';
     $html = $this->buildHtml($styles, $content);
-    $result_html = (string)$this->css->inlineCSS(null, $html);
+    $result_html = (string)$this->css->inlineCSS($html);
     $this->assertContains('<p style="color:red">', $result_html);
   }
 
@@ -49,7 +49,7 @@ class CSSTest extends \MailPoetUnitTest {
     $styles = 'p { color: red; } .blue { color: blue; }';
     $content = '<p class="blue">Foo</p>';
     $html = $this->buildHtml($styles, $content);
-    $result_html = (string)$this->css->inlineCSS(null, $html);
+    $result_html = (string)$this->css->inlineCSS($html);
     $this->assertContains('<p class="blue" style="color:blue">', $result_html);
   }
 
@@ -57,7 +57,7 @@ class CSSTest extends \MailPoetUnitTest {
     $styles = 'p { color: red; }';
     $content = '<p style="color:green">Foo</p>';
     $html = $this->buildHtml($styles, $content);
-    $result_html = (string)$this->css->inlineCSS(null, $html);
+    $result_html = (string)$this->css->inlineCSS($html);
     $this->assertContains('<p style="color:green">', $result_html);
   }
 
@@ -65,7 +65,7 @@ class CSSTest extends \MailPoetUnitTest {
     $styles = 'p { color: red !important; }';
     $content = '<p style="color:green !important">Foo</p>';
     $html = $this->buildHtml($styles, $content);
-    $result_html = (string)$this->css->inlineCSS(null, $html);
+    $result_html = (string)$this->css->inlineCSS($html);
     $this->assertContains('<p style="color:red">', $result_html);
   }