Method to get fit_args after getting necessary variables

def do_bestfit(self):
        """
        Method to get fit_args after getting necessary variables
        """
        self.check_important_variables()
        self.fit_args = np.polyfit(
            self.args["x"], self.args["y"], self.args.get("degree", 1))
        self.done_bestfit = True
        return self.fit_args