def get_start_datetime(self):
        """The start of the acquisition.

        This is a datetime without timezone in UTC.
        """

        # Use the alternate time if available (from EODS_DATASET metadata).
        try:
            start_dt = self._ds.scene_alt_start_datetime
        except __HOLE__:
            start_dt = None

        # Othewise use the original time (calcualted from scene_centre_time).
        if start_dt is None:
            start_dt = self._ds.scene_start_datetime

        return start_dt
dataset/ETHPy150Open GeoscienceAustralia/agdc/src/landsat_ingester/landsat_dataset.py/LandsatDataset.get_start_datetime