add sample

fix undefined Index

samples/Sample_35_InternalLink.php

@@ -0,0 +1,22 @@
+<?php
+include_once 'Sample_Header.php';
+
+// New Word document
+echo date('H:i:s'), " Create new PhpWord object", EOL;
+$phpWord = new \PhpOffice\PhpWord\PhpWord();
+
+$section = $phpWord->addSection();
+$section->addTitle( 'This is page 1', 1 );
+$linkIsInternal = true;
+$section->addLink('MyBookmark', 'Take me to page 3', null ,null,$linkIsInternal);
+$section->addPageBreak();
+$section->addTitle( 'This is page 2', 1 );
+$section->addPageBreak();
+$section->addTitle( 'This is page 3', 1 );
+$section->addBookmark('MyBookmark');
+
+// Save file
+echo write($phpWord, basename(__FILE__, '.php'), $writers);
+if (!CLI) {
+    include_once 'Sample_Footer.php';
+}

src/PhpWord/PhpWord.php

@@ -139,7 +139,7 @@ class PhpWord
             /** @var \PhpOffice\PhpWord\Collection\AbstractCollection $collectionObject */
             $collectionObject = $this->collections[$key];
 
-            return $collectionObject->addItem($args[0]);
+            return $collectionObject->addItem(array_key_exists(0,$args) ? $args[0] : null);
         }
 
         // Run add style method