Draw_lane

def draw_lane(img, left_line, right_line, lane_color=(255, 0,255), road_color=(50, 255,50)):
    """ draw lane lines & current driving space """
    
    window_img = np.zeros_like(img)

    window_margin = left_line.window_margin
    left_plotx, right_plotx = left_line.allx, right_line.allx
    ploty = left_line.ally

    # Generate a polygon to illustrate the search window area
    # And recast the x and y points into usable format for cv2.fillPoly()
    left_pts_l = np.array([np.transpose(np.vstack([left_plotx - window_margin/5, ploty]))])
    left_pts_r = np.array([np.flipud(np.transpose(np.vstack([left_plotx + window_margin/5, ploty])))])
    left_pts = np.hstack((left_pts_l, left_pts_r))
    right_pts_l = np.array([np.transpose(np.vstack([right_plotx - window_margin/5, ploty]))])
    right_pts_r = np.array([np.flipud(np.transpose(np.vstack([right_plotx + window_margin/5, ploty])))])
    right_pts = np.hstack((right_pts_l, right_pts_r))

    # Draw the lane onto the warped blank image
    cv2.fillPoly(window_img, np.int_([left_pts]), lane_color)
    cv2.fillPoly(window_img, np.int_([right_pts]), lane_color)

    # Recast the x and y points into usable format for cv2.fillPoly()
    pts_left = np.array([np.transpose(np.vstack([left_plotx+window_margin/5, ploty]))])
    pts_right = np.array([np.flipud(np.transpose(np.vstack([right_plotx-window_margin/5, ploty])))])
    pts = np.hstack((pts_left, pts_right))

    # Draw the lane onto the warped blank image
    cv2.fillPoly(window_img, np.int_([pts]), road_color)
    result = cv2.addWeighted(img, 1, window_img, 0.3, 0)

    return result, window_img