fixup! Fix all uses of UsageKeys and CourseKeys, and all of their tests.
Replace tabs w/ spaces
fixup! fixup! Implementation of old-style keys as OpaqueKeys (Location and course_id)
fixup! Implementation of old-style keys as OpaqueKeys (Location and course_id)
fixup! Fix all uses of UsageKeys and CourseKeys, and all of their tests.
fixup! Fix all uses of UsageKeys and CourseKeys, and all of their tests.