code: def anticlockwise_sort_indices(pps):
      
      angles = np.zeros(len(pps), np.float)
      for ipp, pp in enumerate(pps):
          angles[ipp] = np.arctan2(pp[1], pp[0])
      return np.argsort(angles)
docs: Returns the indices that would sort a list of 2D points in anticlockwise order
      :param pps: List of points to be sorted
      :return: Indices of the sorted list of points