import pyglet
window=pyglet.window.Window()
label=pyglet.text.Label(
    'Hello, world',
    font_name='Times New Roman'
    ,font_size=36,
    x=window.width//2,
    y=window.height//2,
    anchor_x='center',
    anchor_y='center'
)
@window.event
def on_draw():
    window.clear()
    label.draw()
pyglet.app.run()