[Tutor] Tkinter canvas on frame

[Phil]

This is part of a project I was working on a couple of months ago and I 
didn't notice that there is a problem until today when I added some colours.

The question is, how can I site the canvas on the frame so that the blue 
frame surrounds the canvas? Without the canvas the whole frame is blue. 
I suspect that it's to do with the pack manager.

import tkinter as tk


class Root(tk.Tk):
     def __init__(self):
         super().__init__()
         self.title("Canvas Template")
         self.geometry("400x300")

         self.frame = tk.Frame(background='cornflowerblue')

         self.frame.pack(fill=tk.BOTH, expand=1)

         canvas = tk.Canvas(self, relief='flat', background='lightgrey',
                            width=200, height=200)
         canvas.pack(side=tk.TOP, anchor='nw', padx=10, pady=10)

         quit_button = tk.Button(self, text="Quit", command=self.quit)
         quit_button.pack(side=tk.BOTTOM, anchor='se', padx=10, pady=10)


if __name__ == "__main__":
     root = Root()
     root.mainloop()

-- 
Regards,
Phil