diff --git a/includes/menu/Group.php b/includes/menu/Group.php
index 9bcdcce10..0a5eb1084 100644
--- a/includes/menu/Group.php
+++ b/includes/menu/Group.php
@@ -62,6 +62,18 @@ class Group {
 		return array_map( $entryPresenter, $this->entries );
 	}
 
+	/**
+	 * Helper method to verify that the $name of entry is unique (do not exists
+	 * in current Group )
+	 * @param string $name
+	 * @throws DomainException When the entry already exists
+	 */
+	private function throwIfNotUnique( $name ) {
+		if ( $this->search( $name ) !== -1 ) {
+			throw new DomainException( "The \"${name}\" entry already exists." );
+		}
+	}
+
 	/**
 	 * Insert an entry into the menu.
 	 *
@@ -71,10 +83,7 @@ class Group {
 	 * @return MenuEntry
 	 */
 	public function insert( $name, $isJSOnly = false ) {
-		if ( $this->search( $name ) !== -1 ) {
-			throw new DomainException( "The \"${name}\" entry already exists." );
-		}
-
+		$this->throwIfNotUnique( $name );
 		$this->entries[] = $entry = new MenuEntry( $name, $isJSOnly );
 
 		return $entry;
@@ -109,9 +118,7 @@ class Group {
 	 * @return MenuEntry
 	 */
 	public function insertAfter( $targetName, $name, $isJSOnly = false ) {
-		if ( $this->search( $name ) !== -1 ) {
-			throw new DomainException( "The \"${name}\" entry already exists." );
-		}
+		$this->throwIfNotUnique( $name );
 
 		$index = $this->search( $targetName );