def dog_walk(x, y, say="", speed="normal"):
    print(f"Dog {speed} walk to point ({x}, {y})", end=" ")
    if say:
        print(f"and say '{say}'", end=" ")
    print()


dog_walk(0, 0)
    # Dog normal walk to point (0, 0)

dog_walk(0, 0, "Wuf!")
    # Dog normal walk to point (0, 0) and say 'Wuf!'

dog_walk(0, 0, "Wuf!", "slow")
    # Dog slow walk to point (0, 0) and say 'Wuf!'

dog_walk(0, 0, speed="fast")
    # Dog fast walk to point (0, 0)

dog_walk(say="I am a WULF!", x=100, y=500)
    # Dog normal walk to point (100, 500) and say 'I am a WULF!'