Add padding around four sides of box

        :param px: padding value in pixels.
            Can be an array in the format of [top right bottom left] or single value.
        :return: New padding added box

def padding(self, px):
        """
        Add padding around four sides of box

        :param px: padding value in pixels.
            Can be an array in the format of [top right bottom left] or single value.
        :return: New padding added box
        """
        # if px is not an array, have equal padding all sides
        if not isinstance(px, list):
            px = [px] * 4

        x = max(0, self.x - px[3])
        y = max(0, self.y - px[0])
        x2 = self.x + self.width + px[1]
        y2 = self.y + self.height + px[2]
        return Box.from_xy(x, y, x2, y2)