docs: def get_inters(r, L, R_cut):
      '''
      Return points within a given cut-off of each other,
      in a periodic system.
  
      Uses a cell-list.
  
      Parameters
      ----------
      r: array, shape (n, d) where d is one of (2, 3).
          A set of n point coordinates.
          Coordinates are assumed to lie in [-L / 2, L / 2].
      L: float.
          Bounds of the system.
      R_cut: float.
          The maximum distance within which to consider points to lie
          near each other.
  
      Returns
      -------
      inters: array, shape (n, n)
          Indices of the nearby points.
          For each particle indexed by the first axis,
          the second axis lists each index of a nearby point.
      intersi: array, shape (n,)
          Total number of nearby points.
          This array should be used to index `inters`, as for point `i`,
          elements in `inters[i]` beyond `intersi[i]` have no well-defined value.
      '''
      if r.shape[1] == 2:
          _cell_list.cell_list_2d.make_inters(r.T, L, R_cut)
      elif r.shape[1] == 3:
          _cell_list.cell_list_3d.make_inters(r.T, L, R_cut)
      else:
          print('Warning: cell list not implemented in this dimension, falling'
                'back to direct computation')
          return get_inters_direct(r, L, R_cut)
      return _parse_inters()