`eth_getUncleByBlockHashAndIndex`
        `eth_getUncleByBlockNumberAndIndex`

def getUncleByBlock(self, block_identifier, uncle_index):
        """
        `eth_getUncleByBlockHashAndIndex`
        `eth_getUncleByBlockNumberAndIndex`
        """
        method = select_method_for_block_identifier(
            block_identifier,
            if_predefined='eth_getUncleByBlockNumberAndIndex',
            if_hash='eth_getUncleByBlockHashAndIndex',
            if_number='eth_getUncleByBlockNumberAndIndex',
        )
        result = self.web3.manager.request_blocking(
            method,
            [block_identifier, uncle_index],
        )
        if result is None:
            raise BlockNotFound(
                f"Uncle at index: {uncle_index} of block with id: {block_identifier} not found."
            )
        return result