code: def get_subscribed_services_names(cls):
          
          # This is very inefficient - loops within loops within loops, and
          # many network requests
          # Optimise it?
          accounts_for_service = Account.get_accounts_for_service
          service_data = cls._get_music_services_data().values()
          return [
              service['Name'] for service in service_data
              if len(
                  accounts_for_service(service['ServiceType'])
              ) > 0
          ]
docs: Get a list of the names of all subscribed music services.
  
          Returns:
              list: A list of strings.