diff --git a/Composite/Form.php b/Composite/Form.php
index 18ad54b..e2ebc60 100644
--- a/Composite/Form.php
+++ b/Composite/Form.php
@@ -28,7 +28,7 @@ class Form extends FormElement
      *
      * @return string
      */
-    public function render()
+    public function render($indent = 0)
     {
         $formCode = '';
         foreach ($this->_elements as $element) {
diff --git a/Composite/FormElement.php b/Composite/FormElement.php
index 8c56ac7..3e3de93 100644
--- a/Composite/FormElement.php
+++ b/Composite/FormElement.php
@@ -4,5 +4,5 @@ namespace DesignPatterns\Composite;
 
 abstract class FormElement
 {
-    abstract public function render();
+    abstract public function render($indent = 0);
 }
diff --git a/Composite/InputElement.php b/Composite/InputElement.php
index 0ed7022..d042e72 100644
--- a/Composite/InputElement.php
+++ b/Composite/InputElement.php
@@ -4,7 +4,7 @@ namespace DesignPatterns\Composite;
 
 class InputElement extends FormElement
 {
-    public function render()
+    public function render($indent = 0)
     {
         return '<input type="text" />';
     }
diff --git a/Composite/TextElement.php b/Composite/TextElement.php
index bf5d8cd..9e076e8 100644
--- a/Composite/TextElement.php
+++ b/Composite/TextElement.php
@@ -4,7 +4,7 @@ namespace DesignPatterns\Composite;
 
 class TextElement extends FormElement
 {
-    public function render()
+    public function render($indent = 0)
     {
         return 'this is a text element';
     }