code: def validate(self, data):  # pylint: disable=arguments-differ
          
          lms_user_id = data.get('lms_user_id')
          tpa_user_id = data.get('tpa_user_id')
          user_email = data.get('user_email')
          if not lms_user_id and not tpa_user_id and not user_email:
              raise serializers.ValidationError(
                  'At least one of the following fields must be specified and map to an EnterpriseCustomerUser: '
                  'lms_user_id, tpa_user_id, user_email'
              )
  
          return data
docs: Validate that at least one of the user identifier fields has been passed in.