code: def filter_lane(lane):
      assert lane[-1][1] <= lane[0][1]
      filtered_lane = []
      used = set()
      for p in lane:
          if p[1] not in used:
              filtered_lane.append(p)
              used.add(p[1])
  
      return filtered_lane
  
file_path: PaddleDetection/ppdet/data/culane_utils.py
imports: import math
  import numpy
  from imgaug.augmentables.lines import LineString
  from scipy.interpolate import InterpolatedUnivariateSpline
label_desc: Use image node_id 4 for calling a global function with example usage: filter_lane(lane) and returns: filtered_lane