diff --git a/setup.cfg b/setup.cfg
index 7f28c527d..b5cf191ed 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -50,6 +50,7 @@ putty-ignore =
     tests/*/*/test_*.py : +D100,D101,D401
     tests/*/test_*.py : +D100,D101,D401
     tests/unit/browser/http/test_content_disposition.py : +D400
+    scripts/dev/ci/install.py : +C901
 copyright-check = True
 copyright-regexp = # Copyright [\d-]+ .*
 copyright-min-file-size = 110