get the forecast names from the pestpp options (if any).
        Returns None if no forecasts are named

        Returns
        -------
        forecast_names : list
            a list of forecast names.

def forecast_names(self):
        """get the forecast names from the pestpp options (if any).
        Returns None if no forecasts are named

        Returns
        -------
        forecast_names : list
            a list of forecast names.

        """
        if "forecasts" in self.pestpp_options.keys():
            return self.pestpp_options["forecasts"].lower().split(',')
        elif "predictions" in self.pestpp_options.keys():
            return self.pestpp_options["predictions"].lower().split(',')
        else:
            return None