# File tk/lib/tk/itemconfig.rb, line 357
def __check_available_itemconfigure_options(tagOrId, keys)
id = tagid(tagOrId)
availables = self.__current_itemconfiginfo(id).keys
# add non-standard keys
availables |= __font_optkeys.map{|k|
[k.to_s, "latin#{k}", "ascii#{k}", "kanji#{k}"]
}.flatten
availables |= __item_methodcall_optkeys(id).keys.map{|k| k.to_s}
availables |= __item_keyonly_optkeys(id).keys.map{|k| k.to_s}
keys = _symbolkey2str(keys)
keys.delete_if{|k, v| !(availables.include?(k))}
end