code: def sso(user, desired_username, name, email, profile_fields=None):
      
      if not user:
          if not settings.REGISTRATION_OPEN:
              raise SSOError('Account registration is closed')
          user = _create_desired_user(desired_username)
          _configure_user(user, name, email, profile_fields)
  
      if not user.is_active:
          raise SSOError('Account disabled')
  
      # login() expects the logging in backend to be set on the user.
      # We are bypassing login, so fake it.
      user.backend = settings.AUTHENTICATION_BACKENDS[0]
      return user
docs: Create a user, if the provided `user` is None, from the parameters.
      Then log the user in, and return it.