def last_value(self) -> float:
        """
        Last value of this univariate series.

        Returns
        -------
        float
            The last value of this univariate deterministic time series
        """
        self._assert_univariate()
        self._assert_deterministic()
        return float(self._xa[-1, 0, 0])

        Last value of this univariate series.

        Returns
        -------
        float
            The last value of this univariate deterministic time series
        
darts/timeseries.py