How to pass arguments to a popup menu

I need a context menu to know the widget that called it, and then pass that value to its associated commands.

The only way I've achieved it is by using a global variable.

import tkinter as tk

class Example:

    def __init__(self, window):
        base = tk.Frame(window).pack()
        for i in range(3):
            l = tk.Label(base, text='label '+str(i))
            l.pack()
            l.bind("<Button-1>", lambda event: self.handler(event))

        self.menu = tk.Menu(window, tearoff=0)
        self.menu.add_command(label='test', command=self.test)

    def handler(self, event):
        self.menu.post(event.x_root, event.y_root)
        self.menu.focus_set()
        global widget
        widget = event.widget

    def test(self):
        print ('click on widget: ', widget)

main = tk.Tk()
example = Example(main)
main.mainloop()

Is there another best practice to do this? If possible, without using global variables.