From a7cab513695ba1814d9316719429d63249fb97dc Mon Sep 17 00:00:00 2001
From: Davidrjx <1058960881@qq.com>
Date: Thu, 13 Jul 2017 18:07:36 +0800
Subject: [PATCH] Use a set literal in _clean_settings (#1585)

---
 AUTHORS                   |  1 +
 mongoengine/connection.py | 11 ++++++-----
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/AUTHORS b/AUTHORS
index 1d724718..96a7850e 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -243,3 +243,4 @@ that much better:
  * Victor Varvaryuk
  * Stanislav Kaledin (https://github.com/sallyruthstruik)
  * Dmitry Yantsen (https://github.com/mrTable)
+ * Renjianxin (https://github.com/Davidrjx)
diff --git a/mongoengine/connection.py b/mongoengine/connection.py
index 7eae810f..34ff4dc3 100644
--- a/mongoengine/connection.py
+++ b/mongoengine/connection.py
@@ -146,13 +146,14 @@ def get_connection(alias=DEFAULT_CONNECTION_NAME, reconnect=False):
         raise MongoEngineConnectionError(msg)
 
     def _clean_settings(settings_dict):
-        irrelevant_fields = set([
-            'name', 'username', 'password', 'authentication_source',
-            'authentication_mechanism'
-        ])
+        # set literal more efficient than calling set function
+        irrelevant_fields_set = {
+            'name', 'username', 'password',
+            'authentication_source', 'authentication_mechanism'
+        }
         return {
             k: v for k, v in settings_dict.items()
-            if k not in irrelevant_fields
+            if k not in irrelevant_fields_set
         }
 
     # Retrieve a copy of the connection settings associated with the requested