pub fn new(
    outgoing: SatPoint,
    inscriptions: BTreeMap<SatPoint, InscriptionId>,
    amounts: BTreeMap<OutPoint, Amount>,
    locked_utxos: BTreeSet<OutPoint>,
    recipient: Address,
    change: [Address; 2],
    fee_rate: FeeRate,
    target: Target,
  ) -> Self {
    Self {
      utxos: amounts.keys().cloned().collect(),
      locked_utxos,
      amounts,
      change_addresses: change.iter().cloned().collect(),
      fee_rate,
      inputs: Vec::new(),
      inscriptions,
      outgoing,
      outputs: Vec::new(),
      recipient,
      unused_change_addresses: change.to_vec(),
      target,
    }
  }

  pub fn build_transaction(self) -> Result<Transaction> {
    if self.change_addresses.len() < 2 {
      return Err(Error::DuplicateAddress(
        self.change_addresses.first().unwrap().clone(),
      ));
    }

    if self.change_addresses.contains(&self.recipient) {
      return Err(Error::DuplicateAddress(self.recipient));
    }

    match self.target {
      Target::Value(output_value) | Target::ExactPostage(output_value) => {