from guizero import App, PushButton

def blink():
        if (blinkingbutton.bg == "black"):
                blinkingbutton.bg = "white"
                blinkingbutton.text_color = "black"
        else:
                blinkingbutton.bg = "black"
                blinkingbutton.text_color = "white"

app = App("blinking button")

blinkingbutton = PushButton(app, text="BLINKING BUTTON")
blinkingbutton.bg = "white"
blinkingbutton.text_color = "black"
blinkingbutton.repeat(1000, blink)

app.display()