diff --git a/mypy_self_check.ini b/mypy_self_check.ini
index cb9eb4b2aa35..2b7ed2b157c5 100644
--- a/mypy_self_check.ini
+++ b/mypy_self_check.ini
@@ -18,3 +18,4 @@ show_error_codes = True
 pretty = True
 always_false = MYPYC
 plugins = misc/proper_plugin.py
+python_version = 3.5