我正在尝试一个新命令,但是由于某种原因我遇到了错误。 `TypeError:db.startsWith不是一个函数`

I'm trying a new command, but for some reason I'm getting an error. TypeError: db.startsWith is not a function. Please check the code provided below. Thank you! :) Version: 7.1.1

if(args[0] == 'car') {
   let cars = db.startsWith(`car_${message.guild.id}`, { sort: '.data'})
      let content = "";

   for (let i = 0; i < cars.length; i++) {
      let user = client.users.get(cars[i].ID.split('_')[2]).username

   content += `${i+1}. ${user} ~ ${cars[i].data}\n`
  }