code: protected function resourceFieldsExistInAttributesAndRelationships(iterable $fields): void
      {
          foreach ($fields as $field) {
              $this->errors->add(
                  $this->translator->resourceFieldExistsInAttributesAndRelationships($field)
              );
          }
      }
docs: Add errors for when a resource field exists in both the attributes and relationships members.
  
  @param iterable $fields
  @return void