'Fetch the key:value editable course details for the given course from
persistence and return a CourseMetadata model.'

@classmethod
def fetch(cls, descriptor):

    result = {}
    metadata = cls.fetch_all(descriptor)
    for (key, value) in metadata.iteritems():
        if (key in cls.filtered_list()):
            continue
        result[key] = value
    return result
