a.py

import pyglet

window = pyglet.window.Window()
batch = pyglet.graphics.Batch()
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",
    batch=batch,
)


@window.event
def on_key_press(symbol, modifiers):
    label.delete()


@window.event
def on_draw():
    window.clear()
    batch.draw()


pyglet.app.run()