applescript - Applescript - 「エイリアスのすべてのアイテムを取得できません」という文字を置き換えます

Question

以下は、ファイルの名前を変更する私のコードです。"_"コードは基本的に特殊文字をチェックし、 (アンダースコア)に置き換えます。

コード

set thefile to choose file

    set Filename to my replace_chars(thefile, "   ", " ")
    set Filename to my replace_chars(thefile, "  ", " ")
    set Filename to my replace_chars(thefile, " ", "_")
    set Filename to my replace_chars(thefile, ",", "_")
    set Filename to my replace_chars(thefile, "!", "_")
    set Filename to my replace_chars(thefile, "~", "_")
    set Filename to my replace_chars(thefile, "*", "_")
    set Filename to my replace_chars(thefile, "/", "_")
    set Filename to my replace_chars(thefile, ":", "_")
    set Filename to my replace_chars(thefile, "(", "_")
    set Filename to my replace_chars(thefile, ")", "_")
    set Filename to my replace_chars(thefile, "___", "_")
    set Filename to my replace_chars(thefile, "__", "_")

tell application "Finder"

    set the name of file thefile to "Testing.png"
end tell

on replace_chars(this_text, search_string, replacement_string)
    set AppleScript's text item delimiters to the search_string
    set the item_list to every text item of this_text
    set AppleScript's text item delimiters to the replacement_string
    set this_text to the item_list as string
    set AppleScript's text item delimiters to ""
    return this_text
end replace_chars

投げ"Cant get every text item of alias"ます アドバイスお願いします。