def get_time(self, idx):
        """Return time of data at index `idx`

        Returns nan if the time is not defined"""
        # raw data
        qpi = self.get_qpimage_raw(idx)
        if "time" in qpi.meta:
            thetime = qpi.meta["time"]
        else:
            thetime = np.nan
        return thetime
Return time of data at index `idx`

        Returns nan if the time is not defined