how to delete all objects in a folder with applescript

I want to write an applescript to delete all objects in a folder.This is what i wrote:

tell application "Finder"

deletefiles in folder "/Users/sun/Documents/archive"

end tell

But is didn‘t work ,the error :

error "“Finder”Encountered an error: cannot getting“folder \"/Users/sun/Documents/archive\"”。

error "“Finder”遇到一个错误：不能获得“folder \"/Users/sun/Documents/archive\"”。