message: change static str to use constant.
diff: @@ -252,8 +252,9 @@ impl DeployExt for Deploy {
  const TRANSFER_ARG_TARGET: &str = "target";
  const TRANSFER_ARG_ID: &str = "id";
  - let amount = U512::from_dec_str(amount)
  - .map_err(|err| Error::FailedToParseUint("amount", UIntParseError::FromDecStr(err)))?;
  + let amount = U512::from_dec_str(amount).map_err(|err| {
  + Error::FailedToParseUint(TRANSFER_ARG_AMOUNT, UIntParseError::FromDecStr(err))
  + })?;
  let target = parsing::get_transfer_target(target)?;
  let transfer_id = parsing::transfer_id(transfer_id)?;
  