step4.py

        # Here, we are building the transaction payload that we'll send to write the Trust Anchor identity to the ledger.
        # We submit this transaction under the authority of the steward DID that the ledger already recognizes.
        # This call will look up the private key of the steward DID in our wallet, and use it to sign the transaction.
        print_log('\n7. Building NYM request to add Trust Anchor to the ledger\n')
        nym_transaction_request = await ledger.build_nym_request(submitter_did=steward_did,
                                                                 target_did=trust_anchor_did,
                                                                 ver_key=trust_anchor_verkey,
                                                                 alias=None,
                                                                 role='TRUST_ANCHOR')
        print_log('NYM transaction request: ')
        pprint.pprint(json.loads(nym_transaction_request))

        # Now that we have the transaction ready, send it. The building and the sending are separate steps because some
        # clients may want to prepare transactions in one piece of code (e.g., that has access to privileged backend systems),
        # and communicate with the ledger in a different piece of code (e.g., that lives outside the safe internal
        # network).
        print_log('\n8. Sending NYM request to the ledger\n')
        nym_transaction_response = await ledger.sign_and_submit_request(pool_handle=pool_handle,
                                                                        wallet_handle=wallet_handle,
                                                                        submitter_did=steward_did,
                                                                        request_json=nym_transaction_request)
        print_log('NYM transaction response: ')
        pprint.pprint(json.loads(nym_transaction_response))

        # At this point, we have successfully written a new identity to the ledger. Our next step will be to query it.