/**
  * {@inheritdoc}
  */
 public function delete(\Magento\Eav\Api\Data\AttributeGroupInterface $group)
 {
     /** @var \Magento\Catalog\Model\Product\Attribute\Group $group */
     if ($group->hasSystemAttributes()) {
         throw new StateException(__('Attribute group that contains system attributes can not be deleted'));
     }
     return $this->groupRepository->delete($group);
 }
 /**
  * {@inheritdoc}
  */
 public function assign($entityTypeCode, $attributeSetId, $attributeGroupId, $attributeCode, $sortOrder)
 {
     try {
         $attributeSet = $this->setRepository->get($attributeSetId);
     } catch (NoSuchEntityException $ex) {
         throw new NoSuchEntityException(__('AttributeSet with id "%1" does not exist.', $attributeSetId));
     }
     $setEntityType = $this->entityTypeFactory->create()->getEntityType($attributeSet->getEntityTypeId());
     if ($setEntityType->getEntityTypeCode() != $entityTypeCode) {
         throw new InputException(__('Wrong attribute set id provided'));
     }
     //Check if group exists. If not - expected exception
     $attributeGroup = $this->groupRepository->get($attributeGroupId);
     if ($attributeGroup->getAttributeSetId() != $attributeSetId) {
         throw new InputException(__('Attribute group does not belong to attribute set'));
     }
     /** @var \Magento\Eav\Api\Data\AttributeInterface $attribute */
     $attribute = $this->attributeRepository->get($entityTypeCode, $attributeCode);
     $this->attributeResource->saveInSetIncluding($attribute, $attribute->getAttributeId(), $attributeSetId, $attributeGroupId, $sortOrder);
     $attribute->setAttributeSetId($attributeSetId);
     return $attribute->loadEntityAttributeIdBySet()->getData('entity_attribute_id');
 }