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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def time(self, subname=None, class_=None):
        '''Returns a context manager to time execution of a block of code.

        :keyword subname: The subname to report data to
        :type subname: str
        :keyword class_: The :class:`~statsd.client.Client` subclass to use
            (e.g. :class:`~statsd.timer.Timer` or
            :class:`~statsd.counter.Counter`)
        :type class_: :class:`~statsd.client.Client`

        >>> from statsd import Timer
        >>> timer = Timer('application_name')
        >>>
        >>> with timer.time():
        ...     # resulting timer name: application_name
        ...     pass
        >>>
        >>>
        >>> with timer.time('context_timer'):
        ...     # resulting timer name: application_name.context_timer
        ...     pass

        '''
        if class_ is None:
            class_ = Timer
        timer = self.get_client(subname, class_)
        timer.start()
        yield
        timer.stop('')