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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def transfer_user(self, username, transfer_address, owner_privkey):
 """ Transfer name on blockchain """


        url = self.base_url + "/users/" + username + "/update"

        owner_pubkey = get_pubkey_from_privkey(owner_privkey)

        payload = {
            'transfer_address': transfer_address,
            'owner_pubkey': owner_pubkey
            }

        resp = self._post_request(url, payload)

        try:
            unsigned_tx = resp['unsigned_tx']
        except:
            return resp

        # sign all unsigned inputs
        signed_tx = sign_all_unsigned_inputs(owner_privkey, unsigned_tx)

        return self.broadcast_transaction(signed_tx)