diff --git a/flatisfy/config.py b/flatisfy/config.py
index c9dfd32..802711b 100644
--- a/flatisfy/config.py
+++ b/flatisfy/config.py
@@ -156,7 +156,7 @@ def validate_config(config, check_with_data):
         for constraint in config["constraints"].values():
             assert "type" in constraint
             assert isinstance(constraint["type"], str)
-            assert constraint["type"].upper() in POSTS_TYPES.keys
+            assert constraint["type"].upper() in POSTS_TYPES.__members__
 
             assert "minimum_nb_photos" in constraint
             if constraint["minimum_nb_photos"]:
@@ -172,7 +172,7 @@ def validate_config(config, check_with_data):
             assert "house_types" in constraint
             assert constraint["house_types"]
             for house_type in constraint["house_types"]:
-                assert house_type.upper() in HOUSE_TYPES.keys
+                assert house_type.upper() in HOUSE_TYPES.__members__
 
             assert "postal_codes" in constraint
             assert constraint["postal_codes"]