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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def bitcoin_sig_hash(message):
 """Bitcoin has a special format for hashing messages for signing. :param message: the encoded message to hash in preparation for verifying """

    padded = b'\x18Bitcoin Signed Message:\n' +\
        int_to_var_bytes(len(message)) +\
        message
    return double_sha256(padded)