pushbutton text gui 2

from guizero import App, Text ,PushButton
def do_nothing():
    print("Button was pressed")
app = App(title="Adult Placement Test for English Classes")
testtitle=  Text(app, text="Adult Placement Test for English Classes")
testtitle.text_size=16
testtitle.font = "Arial Black"
startbutton= PushButton(app,command=do_nothing)
startbutton.bg ="green"
startbutton.text = "Start"

app.display()