old_contents: """
  Spotify backend, docs at:
      https://developer.spotify.com/spotify-web-api/
      https://developer.spotify.com/spotify-web-api/authorization-guide/
  """
  import base64
  
  from social.backends.oauth import BaseOAuth2
  
  
  class SpotifyOAuth2(BaseOAuth2):
      name = 'spotify'
      SCOPE_SEPARATOR = ' '
      ID_KEY = 'id'
      AUTHORIZATION_URL = 'https://accounts.spotify.com/authorize'
      ACCESS_TOKEN_URL = 'https://accounts.spotify.com/api/token'
      ACCESS_TOKEN_METHOD = 'POST'
      REDIRECT_STATE = False
      EXTRA_DATA = [
          ('refresh_token', 'refresh_token'),
      ]
  
      def auth_headers(self):
          return {
              'Authorization': 'Basic {0}'.format(base64.urlsafe_b64encode(
                  ('{0}:{1}'.format(*self.get_key_and_secret()).encode())
              ))
          }
  
      def get_user_details(self, response):
          """Return user details from Spotify account"""
          fullname, first_name, last_name = self.get_user_names(
              response.get('display_name')
          )
          return {'username': response.get('id'),
                  'email': response.get('email'),
                  'fullname': fullname,
                  'first_name': first_name,
                  'last_name': last_name}
  
      def user_data(self, access_token, *args, **kwargs):
          """Loads user data from service"""
          return self.get_json(
              'https://api.spotify.com/v1/me',
              headers={'Authorization': 'Bearer {0}'.format(access_token)}
          )
  
new_contents: """
  Spotify backend, docs at:
      https://developer.spotify.com/spotify-web-api/
      https://developer.spotify.com/spotify-web-api/authorization-guide/
  """
  import base64
  
  from social.backends.oauth import BaseOAuth2
  
  
  class SpotifyOAuth2(BaseOAuth2):
      name = 'spotify'
      SCOPE_SEPARATOR = ' '
      ID_KEY = 'id'
      AUTHORIZATION_URL = 'https://accounts.spotify.com/authorize'
      ACCESS_TOKEN_URL = 'https://accounts.spotify.com/api/token'
      ACCESS_TOKEN_METHOD = 'POST'
      REDIRECT_STATE = False
      EXTRA_DATA = [
          ('refresh_token', 'refresh_token'),
      ]
  
      def auth_headers(self):
          auth_str = '{0}:{1}'.format(*self.get_key_and_secret())
          b64_auth_str = base64.urlsafe_b64encode(auth_str.encode()).decode()
          return {
              'Authorization': 'Basic {0}'.format(b64_auth_str)
          }
  
      def get_user_details(self, response):
          """Return user details from Spotify account"""
          fullname, first_name, last_name = self.get_user_names(
              response.get('display_name')
          )
          return {'username': response.get('id'),
                  'email': response.get('email'),
                  'fullname': fullname,
                  'first_name': first_name,
                  'last_name': last_name}
  
      def user_data(self, access_token, *args, **kwargs):
          """Loads user data from service"""
          return self.get_json(
              'https://api.spotify.com/v1/me',
              headers={'Authorization': 'Bearer {0}'.format(access_token)}
          )
  
subject: Fix #703