def eth_getBlockTransactionCountByHash(self, bhash):
        """https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_getblocktransactioncountbyhash

        :param bhash: Block hash
        :type bhash: str

        :return: count
        :rtype: int or None
        """
        response = yield from self.rpc_call('eth_getBlockTransactionCountByHash',
                                            [bhash])
        if response:
            return hex_to_dec(response)
        return response