diff --git a/frappe/website/router.py b/frappe/website/router.py
index fb9cae7d76..9a647e1030 100644
--- a/frappe/website/router.py
+++ b/frappe/website/router.py
@@ -286,14 +286,14 @@ def setup_source(page_info):
 	# load css/js files
 	js_path = os.path.join(page_info.basepath, (page_info.basename or 'index') + '.js')
 	if os.path.exists(js_path):
-		if not '{% block script %}' in html:
+		if '{% block script %}' not in html:
 			with io.open(js_path, 'r', encoding = 'utf-8') as f:
 				js = f.read()
 				page_info.colocated_js = js
 
 	css_path = os.path.join(page_info.basepath, (page_info.basename or 'index') + '.css')
 	if os.path.exists(css_path):
-		if not '{% block style %}' in html:
+		if '{% block style %}' not in html:
 			with io.open(css_path, 'r', encoding='utf-8') as f:
 				css = f.read()
 				page_info.colocated_css = css