code: def login(self, email, password):
          
          r = requests.post('{0}/v2/session'.format(self._api_endpoint),
                            json={'email': email, 'password': password})
          r.raise_for_status()
          return r.json()['accessToken']
docs: Authenticate a user with SignalFx to acquire a session token.
  
          Note that data ingest can only be done with an organization or team API
          access token, not with a user token obtained via this method.
  
          Args:
              email (string): the email login
              password (string): the password
          Returns a new, immediately-usable session token for the logged in user.