new_contents: import toppra
  import toppra.interpolator
  import numpy as np
  import matplotlib.pyplot as plt
  
  
  def test_basic_usage():
      waypoints = [[0, 0.3, 0.5], [1, 2, 3], [0., 0.1, 0.2], [0, 0.5, 0]]
      ss = np.linspace(0, 1, len(waypoints))
      path = toppra.interpolator.SplineInterpolator(ss, waypoints)
  
      gridpoints_ept = toppra.interpolator.propose_gridpoints(path)
  
      # visualize ###############################################################
      ss_full = np.linspace(0, 1, 100)
      for i in range(len(waypoints[0])):
          plt.plot(ss_full, path(ss_full)[:, i], '--', c='C%d' % i)
          plt.plot(gridpoints_ept, path(gridpoints_ept)[:, i], '-o', c='C%d' % i)
      plt.show()
      
      
  
subject: add test for finding gridpoints