def timer(function):
    """ A decorator that makes the decorated *function* return its execution time."""
    @functools.wraps(function)
    def wrapper(*args, **kwargs):
        t1 = time.time()
        result = function(*args, **kwargs)
        t2 = time.time()
        print("  @time '{}': {:.4f} s.".format(str(function), t2-t1))
        return result
    return wrapper

class Timer(object):
    """Use as a context manager:

       with Timer() as t:
           <block>
    """
    def __init__(self, verbose=True):
        self.verbose = verbose

    def __enter__(self):
        self.start = time.time()
        return self

    def __exit__(self, *args):
        self.end = time.time()
        self.secs = self.end - self.start
        self.msecs = self.secs  # millisecs
        if self.verbose:
            print("@Timer: {:.5f} s".format(self.msecs))