diff --git a/docs/user-guide.rst b/docs/user-guide.rst
index 8ac97ea7..e3c8e5ac 100644
--- a/docs/user-guide.rst
+++ b/docs/user-guide.rst
@@ -368,7 +368,7 @@ Or add validation with a drop down.
       'C2:C7',
       ValidationConditionType.one_of_list,
       ['Yes',
-      'No',]
+      'No'],
       showCustomUi=True
    )
 
diff --git a/gspread/http_client.py b/gspread/http_client.py
index b4d74a4b..9aaf448a 100644
--- a/gspread/http_client.py
+++ b/gspread/http_client.py
@@ -115,7 +115,7 @@ def request(
         response = self.session.request(
             method=method,
             url=endpoint,
-            json=json,
+            json=dict(json) if json else None,
             params=params,
             data=data,
             files=files,