code: def get_angle(xs, y_samples):
      xs, ys = xs[xs >= 0], y_samples[xs >= 0]
      if len(xs) > 1:
          LaneEval.lr.fit(ys[:, None], xs)
          k = LaneEval.lr.coef_[0]
          theta = np.arctan(k)
      else:
          theta = 0
      return theta
  
file_path: PaddleSeg/contrib/LaneSeg/third_party/lane.py
imports: import json
  import numpy
  from sklearn.linear_model import LinearRegression
label_desc: Use image node_id 1 for calling the LaneEval obj's underlying member method code with example usage: obj.get_angle(xs, y_samples) and returns: theta