Timing context manager, with indentation for nested timings (http://dabeaz.blogspot.ch/2010/02/context-manager-for-timing-benchmarks.html modified to indent by nested level).

benchmark.py

import threading
import time

bench = threading.local()
class benchmark(object):

    def __init__(self, name):
        self.name = name

    def __enter__(self):
        if getattr(bench, 'level', None) is None:
            bench.level = 0
        else:
            bench.level += 1
        self.start = time.time()

    def __exit__(self, ty, val, tb):
        end = time.time()
        bench.level -= 1
        print("%s%s : %0.3f seconds" % ("    " * bench.level, self.name, end - self.start))
        return False