message: Check acceptance mechanism type isn't empty
diff: @@ -1746,6 +1746,10 @@ pub mod aml_command {
  pub fn set_author_agreement(ctx: &CommandContext, request: &mut String) -> Result<(), ()> {
  if let Some((text, version, acc_mech_type, time_of_acceptance)) = get_transaction_author_info(&ctx) {
  + if acc_mech_type.is_empty(){
  + return Err(println_err!("Transaction author agreement Acceptance Mechanism isn't set."));
  + }
  +
  *request = Ledger::append_txn_author_agreement_acceptance_to_request(&request, Some(&text), Some(&version), None, &acc_mech_type, time_of_acceptance)
  .map_err(|err| handle_indy_error(err, None, None, None))?;
  };
  