Thin wrapper around ``bitcoin.mktx(inputs, outputs)``

        Args:
            inputs (dict): inputs in the form of
                ``{'output': 'txid:vout', 'value': amount in satoshi}``
            outputs (dict): outputs in the form of
                ``{'address': to_address, 'value': amount in satoshi}``
        Returns:
            transaction

def build_transaction(self, inputs, outputs):
        """
        Thin wrapper around ``bitcoin.mktx(inputs, outputs)``

        Args:
            inputs (dict): inputs in the form of
                ``{'output': 'txid:vout', 'value': amount in satoshi}``
            outputs (dict): outputs in the form of
                ``{'address': to_address, 'value': amount in satoshi}``
        Returns:
            transaction
        """
        # prepare inputs and outputs for bitcoin
        inputs = [{'output': '{}:{}'.format(input['txid'], input['vout']),
                   'value': input['amount']} for input in inputs]
        tx = bitcoin.mktx(inputs, outputs)
        return tx