type_util.py 文件源码

def start(self):
        if self._active:
            raise RuntimeError('type checker already running')
        elif self._pending:
            raise RuntimeError('type checker already starting up')
        self._pending = True
        # Install this instance as the current profiler
        self._previous_profiler = sys.getprofile()
        self._set_caller_level_shift(0)
        sys.setprofile(self)

        # If requested, set this instance as the default profiler for all future threads
        # (does not affect existing threads)
        if self.all_threads:
            self._previous_thread_profiler = threading._profile_hook
            threading.setprofile(self)
        self._active, self._pending = True, False