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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 set(self) -> None: """Set the internal flag to ``True``. All waiters are awakened. Calling `.wait` once the flag is set will not block. """

        if not self._value:
            self._value = True

            for fut in self._waiters:
                if not fut.done():
                    fut.set_result(None)