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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 start_waiting(self):
 """ Show waiting progress bar until done_waiting is called. Only has an effect if we are in waiting state. """

        if not self.waiting:
            self.waiting = True
            wait_msg = "Waiting for project to become ready for {}".format(self.msg_verb)
            self.progress_bar.show_waiting(wait_msg)