#The walrus operator := assigns values to variables as part of a larger expression.
#In this example, the assignment expression helps avoid calling len() twice:
if (n := len(a)) > 10:
print(f"List is too long ({n} elements, expected <= 10)")
>>> range(10)[::2]
[0, 2, 4, 6, 8]
seq[start:end:step]