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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 generate_confirmation_key(identity_secret, tag, timestamp):
 """Generate confirmation key for trades. Can only be used once. :param identity_secret: authenticator identity secret :type identity_secret: bytes :param tag: tag identifies what the request, see list below :type tag: str :param timestamp: timestamp to use for generating key :type timestamp: int :return: confirmation key :rtype: bytes Tag choices: * ``conf`` to load the confirmations page * ``details`` to load details about a trade * ``allow`` to confirm a trade * ``cancel`` to cancel a trade """

    data = struct.pack('>Q', int(timestamp)) + tag.encode('ascii') # this will NOT stop working in 2038
    return hmac_sha1(bytes(identity_secret), data)