'If a block was inherited into another structure using copy_from_template,
this will return the original block usage locator from which the
copy was inherited.'

def get_block_original_usage(self, usage_key):

    try:
        store = self._verify_modulestore_support(usage_key.course_key, 'get_block_original_usage')
        return store.get_block_original_usage(usage_key)
    except NotImplementedError:
        return (None, None)
