old_contents: from .oauth import BaseOAuth2
  
  
  class UniverseOAuth2(BaseOAuth2):
      """Universe Ticketing OAuth2 authentication backend"""
      name = 'universe'
      AUTHORIZATION_URL = 'https://www.universe.com/oauth/authorize'
      ACCESS_TOKEN_URL = 'https://www.universe.com/oauth/token'
      BASE_API_URL = 'https://www.universe.com/api'
      USER_INFO_URL = BASE_API_URL + '/v2/current_user'
      ACCESS_TOKEN_METHOD = 'POST'
      STATE_PARAMETER = True
      REDIRECT_STATE = True
      EXTRA_DATA = [
          ('id', 'id'),
          ('slug', 'slug'),
          ('created_at', 'created_at'),
          ('updated_at', 'updated_at'),
      ]
  
      def get_user_id(self, details, response):
          return response['current_user'][self.ID_KEY]
  
      def get_user_details(self, response):
          """Return user details from a Universe account"""
          # Start with the user data as it was returned
          user_details = response['current_user']
          user_details["username"] = user_details["email"]
          return user_details
  
      def user_data(self, access_token, *args, **kwargs):
          """Loads user data from service"""
          return self.get_json(self.USER_INFO_URL, headers={'Authorization': f'Bearer {access_token}'})
  
new_contents: from .oauth import BaseOAuth2
  
  
  class UniverseOAuth2(BaseOAuth2):
      """Universe Ticketing OAuth2 authentication backend"""
      name = 'universe'
      AUTHORIZATION_URL = 'https://www.universe.com/oauth/authorize'
      ACCESS_TOKEN_URL = 'https://www.universe.com/oauth/token'
      BASE_API_URL = 'https://www.universe.com/api'
      USER_INFO_URL = BASE_API_URL + '/v2/current_user'
      ACCESS_TOKEN_METHOD = 'POST'
      STATE_PARAMETER = True
      REDIRECT_STATE = True
      EXTRA_DATA = [
          ('id', 'id'),
          ('slug', 'slug'),
          ('created_at', 'created_at'),
          ('updated_at', 'updated_at'),
      ]
  
      def get_user_id(self, details, response):
          return response['current_user'][self.ID_KEY]
  
      def get_user_details(self, response):
          """Return user details from a Universe account"""
          # Start with the user data as it was returned
          user_details = response['current_user']
          user_details["username"] = user_details["email"]
          return user_details
  
      def user_data(self, access_token, *args, **kwargs):
          """Loads user data from service"""
          return self.get_json(self.USER_INFO_URL, headers={'Authorization': 'Bearer {}'.format(access_token)})
  
subject: Remove f-string for pre-Python 3.6 support.