Fix filter with new opaque key, allowing user to set COURSE_LISTING as old way path

lms/djangoapps/branding/__init__.py

@@ -2,9 +2,9 @@ from xmodule.modulestore.django import modulestore
 from xmodule.course_module import CourseDescriptor
 from django.conf import settings
 
+from opaque_keys.edx.locations import SlashSeparatedCourseKey
 from microsite_configuration import microsite
 
-
 def get_visible_courses():
     """
     Return the set of CourseDescriptors that should be visible in this branded instance
@@ -22,7 +22,7 @@ def get_visible_courses():
 
     # this is legacy format which is outside of the microsite feature -- also handle dev case, which should not filter
     if hasattr(settings, 'COURSE_LISTINGS') and subdomain in settings.COURSE_LISTINGS and not settings.DEBUG:
-        filtered_visible_ids = frozenset(settings.COURSE_LISTINGS[subdomain])
+        filtered_visible_ids = frozenset([SlashSeparatedCourseKey.from_deprecated_string(c) for c in settings.COURSE_LISTINGS[subdomain]])
 
     filtered_by_org = microsite.get_value('course_org_filter')