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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 GetUnavailableBonus(self):
 """ Gets the total claimable amount of Gas in the wallet that is not available to claim because it has not yet been spent. Returns: Fixed8: the amount of Gas unavailable to claim. """

        height = Blockchain.Default().Height + 1
        unspents = self.FindUnspentCoinsByAsset(Blockchain.SystemShare().Hash)
        refs = [coin.Reference for coin in unspents]
        try:
            unavailable_bonus = Blockchain.CalculateBonus(refs, height_end=height)
            return unavailable_bonus
        except Exception as e:
            pass
        return Fixed8(0)