def samples(self):
        """Yield samples as dictionaries, keyed by dimensions."""
        names = self.series.dimensions
        for n, offset in enumerate(self.series.offsets):
            dt = datetime.timedelta(microseconds=offset * 1000)
            d = {"ts": self.ts + dt}
            for name in names:
                d[name] = getattr(self.series, name)[n]
            yield d