You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: api_clearArticleGroup.go
    path of file: ./repos/databag/net/server/internal
    
    the code of the file until where you have to start completion: package databag

import (
	"databag/internal/store"
	"errors"
	"github.com/gorilla/mux"
	"gorm.io/gorm"
	"net/http"
)

//ClearArticleGroup remove sharing group from article
func ClearArticleGroup(w http.ResponseWriter, r *http.Request) {

	account, code, err := ParamAgentToken(r, false)
	if err != nil {
		ErrResponse(w, code, err)
		return
	}

	// scan parameters
	params := mux.Vars(r)
	articleID := params["articleID"]
	groupID := params["groupID"]

	// load referenced article
	var articleSlot store.ArticleSlot
	if err := store.DB.Preload("Article").Where("account_id = ? AND article_slot_id = ?", account.ID, articleID).First(&articleSlot).Error; err != nil {
		if !errors.Is(err, gorm.ErrRecordNotFound) {
			ErrResponse(w, http.StatusInternalServerError, err)
		} else {
			ErrResponse(w, http.StatusNotFound, err)
		}
		return
	}
	if articleSlot.Article == nil {
		ErrResponse(w, http.StatusNotFound, errors.New("article has been deleted"))
		return
	}

	// load referenced group
	var groupSlot store.GroupSlot
	if err := store.DB.Preload("Group.Cards").Where("account_id = ? AND group_slot_id = ?", account.ID, groupID).First(&groupSlot).Error; err != nil {
		if !errors.Is(err, gorm.ErrRecordNotFound) {
			ErrResponse(w, http.StatusInternalServerError, err)
		} else {
			ErrResponse(w, http.StatusNotFound, err)
		}
		return
	}
	if groupSlot.Group == nil {
		ErrResponse(w, http.StatusNotFound, errors.New("group has been deleted"))
		return
	}

	// save and update contact revision
	err = store.DB.Transaction(func(tx *gorm.DB) error {
		if res := tx.Model(&articleSlot.Article).Association("Groups").Delete(groupSlot.Group); res != nil {
			return res
		}
		if res := tx.Model(&articleSlot).Update("revision", account.ArticleRevision+1).Error; res != nil {
			return res
		}
		if res := tx.Model(&account).Update("article_revision", account.ArticleRevision+1).Error; res != nil {
			r
    
func ClearArticleGroup(w http.ResponseWriter, r *http.Request) {

	account, code, err := ParamAgentToken(r, false)
	if err != nil {
		ErrResponse(w, code, err)
		return
	}

	// scan parameters
	params := mux.Vars(r)
	articleID := params["articleID"]
	groupID := params["groupID"]

	// load referenced article
	var articleSlot store.ArticleSlot
	if err := store.DB.Preload("Article").Where("account_id = ? AND article_slot_id = ?", account.ID, articleID).First(&articleSlot).Error; err != nil {
		if !errors.Is(err, gorm.ErrRecordNotFound) {
			ErrResponse(w, http.StatusInternalServerError, err)
		} else {
			ErrResponse(w, http.StatusNotFound, err)
		}
		return
	}
	if articleSlot.Article == nil {
		ErrResponse(w, http.StatusNotFound, errors.New("article has been deleted"))
		return
	}

	// load referenced group
	var groupSlot store.GroupSlot
	if err := store.DB.Preload("Group.Cards").Where("account_id = ? AND group_slot_id = ?", account.ID, groupID).First(&groupSlot).Error; err != nil {
		if !errors.Is(err, gorm.ErrRecordNotFound) {
			ErrResponse(w, http.StatusInternalServerError, err)
		} else {
			ErrResponse(w, http.StatusNotFound, err)
		}
		return
	}
	if groupSlot.Group == nil {
		ErrResponse(w, http.StatusNotFound, errors.New("group has been deleted"))
		return
	}

	// save and update contact revision
	err = store.DB.Transaction(func(tx *gorm.DB) error {
		if res := tx.Model(&articleSlot.Article).Association("Groups").Delete(groupSlot.Group); res != nil {
			return res
		}
		if res := tx.Model(&articleSlot).Update("revision", account.ArticleRevision+1).Error; res != nil {
			return res
		}
		if res := tx.Model(&account).Update("article_revision", account.ArticleRevision+1).Error; res != nil {
			return res
		}
		return nil
	})
	if err != nil {
		ErrResponse(w, http.StatusInternalServerError, err)
		return
	}

	// notify contacts of content change
	SetStatus(account)
	for _, card := range groupSlot.Group.Cards {
		SetContactArticleNotification(account, &card)
	}
	WriteResponse(w, getArticleModel(&articleSlot, true, true))
}