<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def timed_operation(msg, log_start=False):
 """ Surround a context with a timer. Args: msg(str):
 the log to print. log_start(bool):
 whether to print also at the beginning. Example: .. code-block:: python with timed_operation('Good Stuff'):
 time.sleep(1) Will print: .. code-block:: python Good stuff finished, time:1sec. """

    assert len(msg)
    if log_start:
        logger.info('Start {} ...'.format(msg))
    start = timer()
    yield
    msg = msg[0].upper() + msg[1:]
    logger.info('{} finished, time:{:.4f} sec.'.format(
        msg, timer() - start))