ProjectData: add insertUniqueSound method.

Author: narekhovhannisyan

src/ProjectData/ProjectData.php

@@ -10,6 +10,7 @@
 use Renderforest\ProjectData\Screen\Collection\ScreenCollection;
 use Renderforest\ProjectData\Screen\Entity\Screen;
 use Renderforest\ProjectData\Sound\Collection\SoundCollection;
+use Renderforest\Sound\UserSound;
 
 /**
  * Class ProjectData
@@ -341,11 +342,22 @@ public function getSounds(): SoundCollection
         return $this->sounds;
     }
 
+    /**
+     * @return SoundCollection
+     */
+    public function insertUniqueSound(UserSound $sound): ProjectData
+    {
+        $collection = new SoundCollection();
+        $this->sounds = $collection->add($sound);
+
+        return $this;
+    }
+
     /**
      * @param SoundCollection $sounds
      * @return ProjectData
      */
-    public function setSounds(SoundCollection $sounds): ProjectData
+    private function setSounds(SoundCollection $sounds): ProjectData
     {
         $this->sounds = $sounds;