Returns an iterable of uncle headers specified by the given uncles_hash

def get_block_uncles(self, uncles_hash: Hash32) -> List[BlockHeader]:
        """
        Returns an iterable of uncle headers specified by the given uncles_hash
        """
        validate_word(uncles_hash, title="Uncles Hash")
        if uncles_hash == EMPTY_UNCLE_HASH:
            return []
        try:
            encoded_uncles = self.db[uncles_hash]
        except KeyError:
            raise HeaderNotFound(
                "No uncles found for hash {0}".format(uncles_hash)
            )
        else:
            return rlp.decode(encoded_uncles, sedes=rlp.sedes.CountableList(BlockHeader))