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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 _series_sis(self):
 """Return image series in Olympus SIS file."""

        pages = self.pages._getlist(validate=False)
        page = pages[0]
        lenpages = len(pages)
        md = self.sis_metadata
        if 'shape' in md and 'axes' in md:
            shape = md['shape'] + page.shape
            axes = md['axes'] + page.axes
        elif lenpages == 1:
            shape = page.shape
            axes = page.axes
        else:
            shape = (lenpages,) + page.shape
            axes = 'I' + page.axes
        self.is_uniform = True
        return [TiffPageSeries(pages, shape, page.dtype, axes, kind='SIS')]