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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 _create_propose_txn(signer, setting_key_value):
 """Creates an individual sawtooth_settings transaction for the given key and value. """

    setting_key, setting_value = setting_key_value
    nonce = hex(random.randint(0, 2**64))
    proposal = SettingProposal(
        setting=setting_key,
        value=setting_value,
        nonce=nonce)
    payload = SettingsPayload(data=proposal.SerializeToString(),
                              action=SettingsPayload.PROPOSE)

    return _make_txn(signer, setting_key, payload)