Time a block of code

import time
from contextlib import contextmanager


@contextmanager
def timer(label="block"):
    start = time.perf_counter()
    try:
        yield
    finally:
        print(f"{label}: {(time.perf_counter() - start) * 1000:.1f} ms")


with timer("sum of squares"):
    total = sum(n * n for n in range(1_000_000))
print(total)