Fixed #28795 -- Removed 'not in' checks and used dict.setdefault().

2 files changed, 5 insertions, 6 deletions

diff --git a/django/middleware/locale.py b/django/middleware/locale.py
index ee057786ee..2399debf6e 100644
--- a/django/middleware/locale.py
+++ b/django/middleware/locale.py
@@ -57,6 +57,5 @@ class LocaleMiddleware(MiddlewareMixin):
 
         if not (i18n_patterns_used and language_from_path):
             patch_vary_headers(response, ('Accept-Language',))
-        if 'Content-Language' not in response:
-            response['Content-Language'] = language
+        response.setdefault('Content-Language', language)
         return response
diff --git a/django/middleware/security.py b/django/middleware/security.py
index 7bcb72738e..296567432f 100644
--- a/django/middleware/security.py
+++ b/django/middleware/security.py
@@ -37,10 +37,10 @@ class SecurityMiddleware(MiddlewareMixin):
                 sts_header = sts_header + "; preload"
             response["strict-transport-security"] = sts_header
 
-        if self.content_type_nosniff and 'x-content-type-options' not in response:
-            response["x-content-type-options"] = "nosniff"
+        if self.content_type_nosniff:
+            response.setdefault('x-content-type-options', 'nosniff')
 
-        if self.xss_filter and 'x-xss-protection' not in response:
-            response["x-xss-protection"] = "1; mode=block"
+        if self.xss_filter:
+            response.setdefault('x-xss-protection', '1; mode=block')
 
         return response