'Find the location that is the parent of this location in this course.
Returns: version agnostic location (revision always None) as per the rest of mongo.
Args:
revision:
ModuleStoreEnum.RevisionOption.published_only
- return only the PUBLISHED parent if it exists, else returns None
ModuleStoreEnum.RevisionOption.draft_preferred
- return either the DRAFT or PUBLISHED parent,
preferring DRAFT, if parent(s) exists,
else returns None'

def get_parent_location(self, location, revision=ModuleStoreEnum.RevisionOption.published_only, **kwargs):

    parent = self._get_raw_parent_location(location, revision)
    if parent:
        return parent
    return None
