Use list comprehension in model and expect to return None if no rows are

returned

data/model/entitlements.py

@@ -8,9 +8,14 @@ logger = logging.getLogger(__name__)
 
 def get_web_customer_ids(user_id):
     try:
-        customer_ids = []
-        for customer in RedHatSubscriptions.select().where(RedHatSubscriptions.user_id == user_id):
-            customer_ids.append(customer.account_number)
+        customer_ids = [
+            customer.account_number
+            for customer in RedHatSubscriptions.select().where(
+                RedHatSubscriptions.user_id == user_id
+            )
+        ]
+        if len(customer_ids) == 0:
+            return None
         return customer_ids
     except RedHatSubscriptions.DoesNotExist:
         return None

util/marketplace.py

@@ -23,7 +23,7 @@ class RedHatUserApi(object):
     def get_account_number(self, user):
         email = user.email
         account_numbers = entitlements.get_web_customer_ids(user.id)
-        if len(account_numbers) == 0:
+        if account_numbers is None:
             account_numbers = self.lookup_customer_id(email)
             if account_numbers:
                 # store in database for next lookup