title: Gmail - how to use service instance in python?
body: <p>I am trying to use the Gmail history method discussed here: <a href="https://developers.google.com/gmail/api/v1/reference/users/history/list#examples" rel="nofollow noreferrer">https://developers.google.com/gmail/api/v1/reference/users/history/list#examples</a></p>
  
  <p>As a test, I am trying to figure out how to use the python code given. One of the parameters is: <code>service: Authorized Gmail API service instance.</code>
  No datatype is given and it is unclear how to pass that in as a parameter.</p>
  
  <p>I was able to download service credentials as a json and think I may be on the right track, but how would I pass in this json to properly utilize the python function that Gmail provides in the docs? Or is there some other way?</p>