Recreate DEVONthink tags in BibDesk as keywords

tell application "BibDesk"
    --only one item should be selected in BibDesk
    set thePub to the selection of document 1
    set keywordsPub to keywords of (item 1 in thePub)
   
    set old_delimiters to AppleScript's text item delimiters
    --the space inside quotes is very important!
    set AppleScript's text item delimiters to ", "
    set keywordsPubList to text items of keywordsPub
    set AppleScript's text item delimiters to old_delimiters
   
end tell

tell application "DEVONthink Pro"
    set thisSelection to the selection
    if thisSelection is {} then error "Please select something"
    if (length of thisSelection) is greater than 1 then error "Please select only one item"
    set the clipboard to ""
    set thisItem to (item 1 of thisSelection)
    set tagsItem to tags of thisItem
   
    repeat with x from 1 to the count of tagsItem
        set positionOfDuplicate to list_position(item x of tagsItem, keywordsPubList) of me
       
        if positionOfDuplicate is 0 then
            set keywordsPub to keywordsPub & ", " & item x of tagsItem
        else
            set keywordsPub to keywordsPub
        end if
       
    end repeat
   
end tell

tell application "BibDesk"
    if the first character of keywordsPub is "," then
        set keywordsPub to text 3 thru -1 of keywordsPub as text
    end if
    set keywords of (item 1 in the thePub) to keywordsPub
end tell

--subroutine from "AppleScript 1-2-3" p.567 for checking for duplicates
on list_position(this_item, this_list)
    repeat with i from 1 to the count of this_list
        if item i of this_list is this_item then return i
    end repeat
    return 0
end list_position