[Tkinter] canvas.create_text doesn't work in a function

[Windspar]

pass the canvas in the function.

def show_stim(canvas, stim, side, verpos, police):
    #etc
    canvas.create_text(x, y, text=stim.value, fill=stim.color, font=police)

---

or
example

import tkinter as tk
import tkinter.font as font

# global container
class PrimTask:
    pass

def show_stim(stim, side, verpos, police):
    x = PrimTask.screensize[0]/2 + side
    y = PrimTask.screensize[1]/2 + verpos
    PrimTask.canvas.create_text(x, y, text=stim, fill='blue', font=police)

def main():
    PrimTask.screensize = 800, 600
    PrimTask.root = tk.Tk()
    PrimTask.canvas = tk.Canvas(PrimTask.root, background='black',
        height = PrimTask.screensize[1], width = PrimTask.screensize[0])
    PrimTask.canvas.pack()

    #fonts definition
    italic = font.Font(PrimTask.root, family='Times', size=50, slant='italic')
    underline = font.Font(PrimTask.root, family='Times', size=50, underline=1)
    polices=[italic, underline]

    show_stim('lettre', 150, 150, italic)

    PrimTask.root.mainloop()

if __name__ == '__main__':
    main()