a=0
def fill(event):
    a=1
    if a==1:
        drawing_area.configure(background="black")
        is_bind=True
        print(is_bind)
    else:
        is_bind=False
        print(is_bind)

 is_bind=True
print(is_bind)
def fill(event):
    global is_bind
    drawing_area.configure(background="black")
    is_bind=False
    print(is_bind)

 is_bind=True
print(is_bind)
def fill(event, is_bind):
    drawing_area.configure(background="black")
    is_bind=False
    print(is_bind)
#
but1.bind("<Button-1>", lambda event: fill(event, is_bind))

 def motion(event):
    global toolsThickness
    global type_
    global xold, yold
    if b1 == "down":
        if xold is not None and yold is not None:
            method = {"polygon": event.widget.create_polygon(xold,yold,event.x,event.y,
                                                             width=toolsThickness,
                                                             outline="blue"),
                      "oval": event.widget.create_oval(event.x - toolsThickness,
                                                       event.y - toolsThickness,
                                                       event.x + toolsThickness,
                                                       event.y + toolsThickness,
                                                       fill="orange"),}[type_]
    xold = event.x
    yold = event.y