Method to get bestfit line using the defined
        self.bestfit_func method

        args:
            x_min: scalar, default=min(x)
                minimum x value of the line
            x_max: scalar, default=max(x)
                maximum x value of the line
            resolution: int, default=1000
                how many steps between x_min and x_max
        returns:
            [bestfit_x, bestfit_y]

def get_bestfit_line(self, x_min=None, x_max=None, resolution=None):
        """
        Method to get bestfit line using the defined
        self.bestfit_func method

        args:
            x_min: scalar, default=min(x)
                minimum x value of the line
            x_max: scalar, default=max(x)
                maximum x value of the line
            resolution: int, default=1000
                how many steps between x_min and x_max
        returns:
            [bestfit_x, bestfit_y]
        """
        x = self.args["x"]
        if x_min is None:
            x_min = min(x)
        if x_max is None:
            x_max = max(x)
        if resolution is None:
            resolution = self.args.get("resolution", 1000)
        bestfit_x = np.linspace(x_min, x_max, resolution)
        return [bestfit_x, self.bestfit_func(bestfit_x)]