diff --git a/lib/Doctrine/ODM/MongoDB/Types/Type.php b/lib/Doctrine/ODM/MongoDB/Types/Type.php
index 67b18da8cc..d29700e759 100644
--- a/lib/Doctrine/ODM/MongoDB/Types/Type.php
+++ b/lib/Doctrine/ODM/MongoDB/Types/Type.php
@@ -122,11 +122,19 @@ public function convertToPHPValue($value)
         return $value;
     }
 
+    /**
+     * Get the PHP code equivalent to {@see convertToDatabaseValue()}, used in code generator.
+     * Use variables $value for input and $return for output.
+     */
     public function closureToMongo(): string
     {
         return '$return = $value;';
     }
 
+    /**
+     * Get the PHP code equivalent to {@see convertToPHPValue()}, used in code generator.
+     * Use variables $value for input and $return for output.
+     */
     public function closureToPHP(): string
     {
         return '$return = $value;';