code: def test_decimation_almost_empty():
      N_1 = 4
      decimation_factor = 666  # greater than N_1
      ptr = torch.tensor([0, N_1])
  
      idx_decim, ptr_decim = decimation_indices(ptr, decimation_factor)
  
      assert idx_decim.size(0) == 1
      assert torch.equal(ptr_decim, torch.tensor([0, 1]))
  
imports: import torch
  from torch_geometric.nn.pool.decimation import decimation_indices
label_desc: Use image node_id 3 for calling a global function with example usage: test_decimation_almost_empty() without return types