How to use the gear.utils.types.decode_hex function in gear

def scrypt_hash(val, params):
    return scrypt.hash(str(val), decode_hex(params["salt"]), params["n"],
                       params["r"], params["p"], params["dklen"])

raise Exception("Hash algo %s not supported" % kdf)
    kdfeval = kdfs[kdf]["calc"]
    # Get cipher and parameters
    cipherparams = cryptdata["cipherparams"]
    cipher = cryptdata["cipher"]
    if cryptdata["cipher"] not in ciphers:
        raise Exception("Encryption algo %s not supported" % cipher)
    decrypt = ciphers[cipher]["decrypt"]
    # Compute the derived key
    derivedkey = kdfeval(pw, kdfparams)
    assert len(derivedkey) >= 32, \
        "Derived key must be at least 32 bytes long"
    # print(b'derivedkey: ' + encode_hex(derivedkey))
    enckey = derivedkey[:16]
    # print(b'enckey: ' + encode_hex(enckey))
    ctext = decode_hex(cryptdata["ciphertext"])
    # Decrypt the ciphertext
    o = decrypt(ctext, enckey, cipherparams)
    # Compare the provided MAC with a locally computed MAC
    # print(b'macdata: ' + encode_hex(derivedkey[16:32] + ctext))
    mac1 = sha3(derivedkey[16:32] + ctext)
    mac2 = decode_hex(cryptdata["mac"])
    if mac1 != mac2:
        raise ValueError("MAC mismatch. Passcode incorrect?")
    return encode_hex(o)

raise Exception("Encryption algo %s not supported" % cipher)
    decrypt = ciphers[cipher]["decrypt"]
    # Compute the derived key
    derivedkey = kdfeval(pw, kdfparams)
    assert len(derivedkey) >= 32, \
        "Derived key must be at least 32 bytes long"
    # print(b'derivedkey: ' + encode_hex(derivedkey))
    enckey = derivedkey[:16]
    # print(b'enckey: ' + encode_hex(enckey))
    ctext = decode_hex(cryptdata["ciphertext"])
    # Decrypt the ciphertext
    o = decrypt(ctext, enckey, cipherparams)
    # Compare the provided MAC with a locally computed MAC
    # print(b'macdata: ' + encode_hex(derivedkey[16:32] + ctext))
    mac1 = sha3(derivedkey[16:32] + ctext)
    mac2 = decode_hex(cryptdata["mac"])
    if mac1 != mac2:
        raise ValueError("MAC mismatch. Passcode incorrect?")
    return encode_hex(o)

def data_gas(data):
    data = decode_hex(data)
    if len(data) == 0:
        return 0
    z = 0
    nz = 0
    for byt in data:
        if byt == 0:
            z += 1
        else:
            nz += 1
    return (TX_DATA_ZERO_GAS * z) + (TX_DATA_NON_ZERO_GAS * nz)

def __init__(self, chain_tag, blk_ref, eth_tx):
        receiver = b"" if "to" not in eth_tx else decode_hex(eth_tx["to"])
        clauses = [
            Clause(
                receiver,
                eth_tx.get("value", 0),
                decode_hex(eth_tx.get("data", "")),
            )
        ]
        super(ThorTransaction, self).__init__(chain_tag, blk_ref, (2 ** 32) - 1, clauses, 0, eth_tx.get("gas", 3000000), b"", 0, [], b"")

def aes_ctr_decrypt(text, key, params):
    iv = big_endian_to_int(decode_hex(params["iv"]))
    ctr = Counter.new(128, initial_value=iv, allow_wraparound=True)
    mode = AES.MODE_CTR
    encryptor = AES.new(key, mode, counter=ctr)
    return encryptor.decrypt(text)

def __init__(self, chain_tag, blk_ref, eth_tx):
        receiver = b"" if "to" not in eth_tx else decode_hex(eth_tx["to"])
        clauses = [
            Clause(
                receiver,
                eth_tx.get("value", 0),
                decode_hex(eth_tx.get("data", "")),
            )
        ]
        super(ThorTransaction, self).__init__(chain_tag, blk_ref, (2 ** 32) - 1, clauses, 0, eth_tx.get("gas", 3000000), b"", 0, [], b"")

def aes_ctr_encrypt(text, key, params):
    iv = big_endian_to_int(decode_hex(params["iv"]))
    ctr = Counter.new(128, initial_value=iv, allow_wraparound=True)
    mode = AES.MODE_CTR
    encryptor = AES.new(key, mode, counter=ctr)
    return encryptor.encrypt(text)

def pbkdf2_hash(val, params):
    assert params["prf"] == "hmac-sha256"
    return pbkdf2.PBKDF2(val, decode_hex(params["salt"]), params["c"],
                         SHA256).read(params["dklen"])