docs: 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