diff --git a/README.md b/README.md
index 0fdd77f..d009172 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 PHP API library following Deepr specification.
 
-![](https://img.shields.io/badge/phpunit-passed-success) ![](https://img.shields.io/badge/coverage-96%25-green) ![](https://img.shields.io/github/stars/stefanak-michal/deepr-php) ![](https://img.shields.io/packagist/dt/stefanak-michal/deepr-php) ![](https://img.shields.io/github/v/release/stefanak-michal/deepr-php) ![](https://img.shields.io/github/commits-since/stefanak-michal/deepr-php/latest)
+![](https://img.shields.io/badge/phpunit-passed-success) ![](https://img.shields.io/badge/coverage-97%25-green) ![](https://img.shields.io/github/stars/stefanak-michal/deepr-php) ![](https://img.shields.io/packagist/dt/stefanak-michal/deepr-php) ![](https://img.shields.io/github/v/release/stefanak-michal/deepr-php) ![](https://img.shields.io/github/commits-since/stefanak-michal/deepr-php/latest)
 
 ## Usage
 
diff --git a/src/Deepr.php b/src/Deepr.php
index 938556b..b735356 100644
--- a/src/Deepr.php
+++ b/src/Deepr.php
@@ -254,21 +254,25 @@ private function recursion(IComponent &$root, string $action, array $values)
 
                 if (method_exists($root, $key)) {
                     $data = $root->{$key}(...$v['()']);
-                    if ($root === $data) {
-                        $root = new Collection();
+
+                    if (is_null($data)) {
+                        $this->recursion($root, $key, $v);
+                        $collection = new Collection();
+                        $collection->add($root, $k);
+                        $root = $collection;
+                        return;
                     }
-                    if ($data instanceof Collection && count($data->getChildren())) {
-                        foreach ($data->getChildren() as $child) {
+
+                    if ($root === $data)
+                        $root = new Collection();
+                    if ($data instanceof Collection) {
+                        foreach ($data->getChildren() as $child)
                             $this->recursion($child, '', $v);
-                        }
-                    } else {
-                        $this->recursion($data, $key, $v);
-                    }
-                    $root->add($data, $k);
-                } elseif ($root instanceof Collection && count($root->getChildren()) && method_exists($root->getChildren()[0], $key)) {
-                    foreach ($root->getChildren() as $child) {
-                        $this->recursion($child, $k, $v);
                     }
+                    if ($data instanceof IComponent)
+                        $root->add($data, $k);
+                    else
+                        throw new Exception('Method has to return instance of IComponent or null', self::ERROR_STRUCTURE);
                 } elseif (strpos($k, '?') === false) {
                     throw new Exception('Missing method ' . $key, self::ERROR_MISSING);
                 }
diff --git a/tests/classes/Movie.php b/tests/classes/Movie.php
index 31405b6..bd6aa2c 100644
--- a/tests/classes/Movie.php
+++ b/tests/classes/Movie.php
@@ -58,10 +58,9 @@ public function getActors(): IComponent
      * RPC method to get movie by title. Use it with source values call.
      * {"<=": {"_type": "Movie"}, "byTitle": {"()": ["The Matrix"]}}
      * @param string $title
-     * @return Movie
      * @see \Deepr\tests\classes\Movie
      */
-    public function byTitle(string $title): Movie
+    public function byTitle(string $title)
     {
         $row = Database::getMovieByTitle($title);
         if (!empty($row)) {
@@ -70,7 +69,6 @@ public function byTitle(string $title): Movie
             $this->released = $row['released'];
             $this->tagline = $row['tagline'];
         }
-        return $this;
     }
 
 }