How profilers work - collecting stats with decorator

profile_stats.py

def profile_stats(func):
    def wrapper(*args, **kwargs):
        start_time = time.time()
        func_name = func.__name__
        # We need this small hack to keep things simple.
        caller_name = sys._getframe(1).f_code.co_name
        result = func(*args, **kwargs)
        stats[func_name][caller_name] += time.time() - start_time
        return result
    return wrapper