code: def select_inputs(self, amount):
        '''Maximize transaction priority. Select the oldest inputs,
        that are sufficient to cover the spent amount. Then,
        remove any unneeded inputs, starting with
        the smallest in value.
        Returns sum of amounts of inputs selected'''
        sorted_txin = sorted(self.ins, key=lambda x:-x['input']['confirmations'])
        total_amount = 0
        for (idx, tx_in) in enumerate(sorted_txin):
          total_amount += tx_in['input']['amount']
          if (total_amount >= amount):
            break
        sorted_txin = sorted(sorted_txin[:idx+1], key=lambda x:x['input']['amount'])
        for (idx, tx_in) in enumerate(sorted_txin):
          value = tx_in['input']['amount']
          if (total_amount - value < amount):
            break
          else:
            total_amount -= value
        self.ins = sorted_txin[idx:]
        return total_amounf select_inputs(self, amount):
        '''Maximize transaction priority. Select the oldest inputs,
        that are sufficient to cover the spent amount. Then,
        remove any unneeded inputs, starting with
        the smallest in value.
        Returns sum of amounts of inputs selected'''
        sorted_txin = sorted(self.ins, key=lambda x:-x['input']['confirmations'])
        total_amount = 0
        for (idx, tx_in) in enumerate(sorted_txin):
          total_amount += tx_in['input']['amount']
          if (total_amount >= amount):
            break
        sorted_txin = sorted(sorted_txin[:idx+1], key=lambda x:x['input']['amount'])
        for (idx, tx_in) in enumerate(sorted_txin):
          value = tx_in['input']['amount']
          if (total_amount - value < amount):
            break
          else:
            total_amount -= value
        self.ins = sorted_txin[idx:]
        return total_amount
docs: Maximize transaction priority. Select the oldest inputs,
        that are sufficient to cover the spent amount. Then,
        remove any unneeded inputs, starting with
        the smallest in value.
        Returns sum of amounts of inputs selected