code: def _check_groups(s, groups):
      
      ans = []
      for g in groups:
          ans.extend(g)
      if np.unique(ans).size != np.size(ans):
          return False
      elif np.unique(ans).size != s.obj_get_positions().shape[0]:
          return False
      else:
          return (np.arange(s.obj_get_radii().size) == np.sort(ans)).all()
docs: Ensures that all particles are included in exactly 1 group