code: def test_warn_slice_negative_index(self):
      with pytest.warns((FionaDeprecationWarning, RuntimeWarning)):
          self.c[2:-4]
  
file_path: Fiona/tests/test_non_counting_layer.py
imports: import unittest
  import pytest
  import fiona
  from fiona.errors import FionaDeprecationWarning
label_desc: Use image node_id 8 for calling the TestNonCountingLayer obj's underlying member method code with example usage: obj.test_warn_slice_negative_index() without return types