From 5998fc7a8e4ecd67b4d1998940d66b426e74cc64 Mon Sep 17 00:00:00 2001
From: Prabhupad Pradhan <prabhupad26@gmail.com>
Date: Thu, 4 Aug 2022 17:04:04 +0200
Subject: [PATCH] Added null check for Issue # 2681

---
 mongoengine/base/fields.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mongoengine/base/fields.py b/mongoengine/base/fields.py
index a68035274..8f1595900 100644
--- a/mongoengine/base/fields.py
+++ b/mongoengine/base/fields.py
@@ -511,7 +511,8 @@ def to_python(self, value):
     def to_mongo(self, value):
         if not isinstance(value, ObjectId):
             try:
-                return ObjectId(str(value))
+                if value:
+                    return ObjectId(str(value))
             except Exception as e:
                 self.error(str(e))
         return value