diff --git a/setup.cfg b/setup.cfg
index 750b4c12cc..91a9a78c13 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -49,5 +49,8 @@ ignore_errors = True
 [mypy-openfisca_core.indexed_enums.tests.*]
 ignore_errors = True
 
+[mypy-openfisca_core.periods.tests.*]
+ignore_errors = True
+
 [mypy-openfisca_core.scripts.*]
 ignore_errors = True