def set_witness(self, tx_idx_in, witness):
        """Set the witness data for a given :class:`TxIn`.

        :param tx_idx_in: an integer index corresponding to the txs_in puzzle script entry that this is a witness to
        :param witness: a list of binary blobs that witness the solution to the given puzzle script
        """
        self.txs_in[tx_idx_in].witness = tuple(witness)