code: def test_object_delitem_warning():
      """Warn about __delitem__"""
      obj = Object(g=1)
      with pytest.warns(FionaDeprecationWarning, match="immutable"):
          del obj["g"]
      assert "g" not in obj
  
imports: import pytest
  from fiona.errors import FionaDeprecationWarning
  from fiona.model import _Geometry, Feature, Geometry, Object, ObjectEncoder, Properties, decode_object
label_desc: Use image node_id 6 for calling a global function with example usage: test_object_delitem_warning() without return types