text: import requests
  
  from .oauth import BaseOAuth2
  from ..exceptions import AuthFailed
  from ..utils import handle_http_errors
  
  
  class UntappdOAuth2(BaseOAuth2):
      """Untappd OAuth2 authentication backend"""
      name = 'untappd'
      AUTHORIZATION_URL = 'https://untappd.com/oauth/authenticate/'
      ACCESS_TOKEN_URL = 'https://untappd.com/oauth/authorize/'
      BASE_API_URL = 'https://api.untappd.com'
      USER_INFO_URL = BASE_API_URL + '/v4/user/info/'
      ACCESS_TOKEN_METHOD = 'GET'
      STATE_PARAMETER = False
      REDIRECT_STATE = False
      EXTRA_DATA = [
          ('id', 'id'),
          ('bio', 'bio'),
          ('date_joined', 'date_joined'),
          ('location', 'location'),
          ('url', 'url'),
          ('user_avatar', 'user_avatar'),
          ('user_avatar_hd', 'user_avatar_hd'),
          ('user_cover_photo', 'user_cover_photo')
      ]
  
      def auth_params(self, state=None):
          client_id, client_secret = self.get_key_and_secret()
          params = {
              'client_id': client_id,
              'redirect_url': self.get_redirect_uri(),
              'response_type': self.RESPONSE_TYPE
          }
          return params
  
      def process_error(self, data):
          """
          All errors from Untappd are contained in the 'meta' key of the
          response.
          """
          response_code = data.get('meta', {}).get('http_code')
          if response_code is not None and response_code != requests.codes.ok:
              raise AuthFailed(self, data['meta']['error_detail'])
  
      @handle_http_errors
      def auth_complete(self, *args, **kwargs):
          """Completes login process, must return user instance"""
          client_id, client_secret = self.get_key_and_secret()
          code = self.data.get('code')
  
          self.process_error(self.data)
  
          # Untapped sends the access token request with URL parameters,
          # not a body
          response = self.request_access_token(
              self.access_token_url(),
              method=self.ACCESS_TOKEN_METHOD,
              params={
                  'response_type': 'code',
                  'code': code,
                  'client_id': client_id,
                  'client_secret': client_secret,
                  'redirect_url': self.get_redirect_uri()
              }
          )
  
          self.process_error(response)
  
          # Both the access_token and the rest of the response are
          # buried in the 'response' key
          return self.do_auth(
              response['response']['access_token'],
              response=response['response'],
              *args, **kwargs
          )
  
      def get_user_details(self, response):
          """Return user details from an Untappd account"""
          # Start with the user data as it was returned
          user_data = response['user']
  
          # Make a few updates to match expected key names
          user_data.update({
              'username': user_data.get('user_name'),
              'email': user_data.get('settings', {}).get('email_address', ''),
              'first_name': user_data.get('first_name'),
              'last_name': user_data.get('last_name'),
              'fullname': user_data.get('first_name') + ' ' +
                          user_data.get('last_name')
          })
          return user_data
  
      def get_user_id(self, details, response):
          """
          Return a unique ID for the current user, by default from
          server response.
          """
          return response['user'].get(self.ID_KEY)
  
      def user_data(self, access_token, *args, **kwargs):
          """Loads user data from service"""
          response = self.get_json(self.USER_INFO_URL, params={
              'access_token': access_token,
              'compact': 'true'
          })
          self.process_error(response)
  
          # The response data is buried in the 'response' key
          return response['response']
  