def list_calibrations(
        self,
        earliest_timestamp: datetime.datetime | datetime.date | int | None = None,
        latest_timestamp: datetime.datetime | datetime.date | int | None = None,
    ) -> list[calibration.Calibration]:
        """Retrieve metadata about a specific calibration run.

        Params:
            earliest_timestamp: The earliest timestamp of a calibration to return in UTC.
            latest_timestamp: The latest timestamp of a calibration to return in UTC.

        Returns:
            The list of calibration data with the most recent first.
        """
        earliest_timestamp_seconds = _date_to_timestamp(earliest_timestamp)
        latest_timestamp_seconds = _date_to_timestamp(latest_timestamp)

        if earliest_timestamp_seconds and latest_timestamp_seconds:
            filter_str = (
                f'timestamp >= {earliest_timestamp_seconds:d} AND '
                f'timestamp <= {latest_timestamp_seconds:d}'
            )
        elif earliest_timestamp_seconds:
            filter_str = f'timestamp >= {earliest_timestamp_seconds:d}'
        elif latest_timestamp_seconds:
            filter_str = f'timestamp <= {latest_timestamp_seconds:d}'
        else:
            filter_str = ''
        response = self.context.client.list_calibrations(
            self.project_id, self.processor_id, filter_str
        )
        return [_to_calibration(c.data) for c in list(response)]
Retrieve metadata about a specific calibration run.

        Params:
            earliest_timestamp: The earliest timestamp of a calibration to return in UTC.
            latest_timestamp: The latest timestamp of a calibration to return in UTC.

        Returns:
            The list of calibration data with the most recent first.
        
cirq-google/cirq_google/engine/engine_processor.py