Tkinter 甚至不能调用一个简单的“按钮”

Question

从简单的 Tkinter 课程开始，即使简单的代码不起作用，我也陷入了困境：import tkinter as tkroot = tk.Tk()b = tk.Button(root, text='button'); b.pack()...Traceback (most recent call last):  File "<stdin>", line 1, in <module>  File "/Users/../anaconda3/lib/python3.6/tkinter/__init__.py", line 2366, in __init__    Widget.__init__(self, master, 'button', cnf, kw)  File "/Users/../anaconda3/lib/python3.6/tkinter/__init__.py", line 2296, in __init__    (widgetName, self._w) + extra + self._options(cnf))_tkinter.TclError: can't invoke "button" command: application has been destroyed并且找不到原因，考虑到此代码来自官方文档。另一方面，另一个代码有效：import tkinter as tkclass Application(tk.Frame):    def __init__(self, master=None):        super().__init__(master)        self.master = master        self.pack()        self.create_widgets()    def create_widgets(self):        self.hi_there = tk.Button(self)        self.hi_there["text"] = "Hello World\n(click me)"        self.hi_there["command"] = self.say_hi        self.hi_there.pack(side="top")        self.quit = tk.Button(self, text="QUIT", fg="red",                              command=self.master.destroy)        self.quit.pack(side="bottom")    def say_hi(self):        print("hi there, everyone!")root = tk.Tk()app = Application(master=root)app.mainloop()我试图tk从 conda:更新conda install -c anaconda tk，但没有任何变化。想不通为什么