Tuple of :obj:`dict`: Inputs of this transaction. Each input
        is represented as a dictionary containing a transaction id and
        output index.

def spent_outputs(self):
        """Tuple of :obj:`dict`: Inputs of this transaction. Each input
        is represented as a dictionary containing a transaction id and
        output index.
        """
        return (
            input_.fulfills.to_dict()
            for input_ in self.inputs if input_.fulfills
        )