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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 closed(self):
 """True if connection is closed."""

        closed = self._closing or self._closed
        if not closed and self._reader and self._reader.at_eof():
            self._closing = closed = True
            self._loop.call_soon(self._do_close, None)
        return closed