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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 _invert_all(self):
 """Invert every bit."""

        set = self._datastore.setbyte
        get = self._datastore.getbyte
        for p in xrange(self._datastore.byteoffset, self._datastore.byteoffset + self._datastore.bytelength):
            set(p, 256 + ~get(p))