Fix a typo

coin/billing/management/commands/charge_subscriptions.py

@@ -27,7 +27,7 @@ class Command(BaseCommand):
         with respect_language(settings.LANGUAGE_CODE):
             invoices = create_all_members_invoices_for_a_period(date)
 
-        if invoices > 0 or verbosity >= 2:
+        if len(invoices) > 0 or verbosity >= 2:
             self.stdout.write(
                 u'%d invoices were created' % len(invoices))