Tkinter保存模型，结合pickle和filedialog

Question

我试图用pickle&；filedialog，但模型不是以sav格式保存，而是以不正确打开的文件格式保存。这是我的代码：

    filename = str (element_u) + "_" + str ((",".join (pls_crop))) + "_" + str (whichButton) # File name extract according to user selected of elment & crop
    export_file_path = filedialog.asksaveasfilename (initialdir=os.getcwd (),initialfile=filename,defaultextension='.pkl')
    pickle.dump (model_RF, open (filename, 'wb'))