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: delete.go
    path of file: ./repos/wal-g/cmd/mongo
    
    the code of the file until where you have to start completion: package mongo

import (
	"time"

	"github.com/spf13/cobra"
	"github.com/wal-g/tracelog"
	"github.com/wal-g/wal-g/internal"
	"github.com/wal-g/wal-g/internal/databases/mongo"
	"github.com/wal-g/wal-g/internal/databases/mongo/archive"
)

const (
	retainAfterFla
    
func init() {
	cmd.AddCommand(deleteCmd)
	deleteCmd.Flags().BoolVar(&confirmed, internal.ConfirmFlag, false, "Confirms backup, garbage and oplog deletion."+
		" If `retainAfterFlag` and `retainCountFlag` are not specified then all backups will be retained.")

	deleteCmd.Flags().BoolVar(&purgeOplog, purgeOplogFlag, false, "Purge oplog archives")
	deleteCmd.Flags().BoolVar(&purgeGarbage, purgeGarbageFlag, false, "Purge garbage in backup folder")
	deleteCmd.Flags().StringVar(&retainAfter, retainAfterFlag, "", "Keep backups newer")
	deleteCmd.Flags().UintVar(&retainCount, retainCountFlag, 0, "Keep minimum count, except permanent backups")
}