I think this lab is missing a step in setting up a security account

When I run transactions.py from the cloud shell in my sandbox project I get this error: The above exception was the direct cause of the following exception: Traceback (most recent call last): File "/usr/local/lib/python3.7/dist-packages/google/cloud/pubsub_v1/publisher/_batch/thread.py", line 272, in _commit timeout=self._commit_timeout, File "/usr/local/lib/python3.7/dist-packages/google/pubsub_v1/services/publisher/client.py", line 612, in publish response = rpc(request, retry=retry, timeout=timeout, metadata=metadata,) File "/usr/local/lib/python3.7/dist-packages/google/api_core/gapic_v1/method.py", line 145, in call return wrapped_func(*args, *kwargs) File "/usr/local/lib/python3.7/dist-packages/google/api_core/retry.py", line 291, in retry_wrapped_func on_error=on_error, File "/usr/local/lib/python3.7/dist-packages/google/api_core/retry.py", line 189, in retry_target return target() File "/usr/local/lib/python3.7/dist-packages/google/api_core/timeout.py", line 102, in func_with_timeout return func(args, **kwargs) File "/usr/local/lib/python3.7/dist-packages/google/api_core/grpc_helpers.py", line 69, in error_remapped_callable six.raise_from(exceptions.from_grpc_error(exc), exc) File "", line 3, in raise_from google.api_core.exceptions.Unauthenticated: 401 Request had invalid authentication credentials. Expected OAuth 2 access token, login cookie or other valid authentication credential. See https://developers.google.com/identity/sign-in/web/devconsole-project.