Consider the option policy product to remain None

ssg/controls.py

@@ -352,7 +352,7 @@ def load(self):
  yaml_product = yaml_contents.get("product", None)
  if type(yaml_product) is list:
  self.product = yaml_product
- else:
+ elif yaml_product is not None:
  self.product = [yaml_product]
 
  default_level_dict = {"id": "default"}