static fromWif(_private_wif) {
        var private_wif = new Buffer.from(base58.decode(_private_wif));
        var version = private_wif.readUInt8(0);
        assert.equal(0x80, version, `Expected version ${0x80}, instead got ${version}`);
        // checksum includes the version
        var private_key = private_wif.slice(0, -4);
        var checksum = private_wif.slice(-4);
        var new_checksum = hash.sha256(private_key);
        new_checksum = hash.sha256(new_checksum);
        new_checksum = new_checksum.slice(0, 4);
        if (checksum.toString() !== new_checksum.toString())
            throw new Error('Invalid WIF key (checksum miss-match)')

        private_key = private_key.slice(1);
        return PrivateKey.fromBuffer(private_key);
    }
@throws {AssertError|Error} parsing key
        @return {string} Wallet Import Format (still a secret, Not encrypted)