In the codelabs, upto slide 7 we are told to create a file named "client_secret.json", however in the slide 8 within the code following lines are used
if not creds or creds.invalid:
flow = client.flow_from_clientsecrets('client_id.json', SCOPES)
creds = tools.run_flow(flow, store)
Here 'client_id.json' should actually be 'client_secret.json'
In the slide 7 where are being told to choose the "Application Type", codelabs used "Other" application type which is now not present anymore. The picture needs to be updated there with option "Desktop App" instead of "Other".
Here 'client_id.json' should actually be 'client_secret.json'