How to use the pyscroll.TiledMapData function in pyscroll

def __init__(self, filename):
        self.init_buffer([screen.get_width() / 2, screen.get_height() / 2])

        tmx_data = pytmx.load_pygame("desert.tmx")
        map_data = pyscroll.TiledMapData(tmx_data)
        self.map_layer = pyscroll.BufferedRenderer(map_data, self.buffer_size)

        f = pygame.font.Font(pygame.font.get_default_font(), 20)
        t = ["scroll demo. press escape to quit",
             "arrow keys move"]

        self.text_overlay = [f.render(i, 1, (180, 180, 0)) for i in t]
        self.center = [self.map_layer.width/2,self.map_layer.height/2]
        self.camera_vector = [0, 0, 0]
        self.running = False