class_docstr: Test advanced pickler and unpickler functionality supported by the
  .hvz format.
code: def test_pickler_save_load_layout_entries(self, tmp_path):
      Pickler.save(
          self.image1 + self.image2,
          tmp_path / "test_pickler_save_load_layout_entries",
          info={"info": "example"},
          key={1: 2},
      )
      entries = Unpickler.entries(
          tmp_path / "test_pickler_save_load_layout_entries.hvz"
      )
      assert entries == ["Image.I", "Image.II"]
  
imports: import numpy
  from holoviews import Image, Layout
  from holoviews.core.io import Deserializer, Pickler, Serializer, Unpickler
  from holoviews.element.comparison import assert_element_equal
label_desc: Use image node_id 4 for calling the TestPicklerAdvanced obj's underlying member method code with example usage: obj.test_pickler_save_load_layout_entries(tmp_path) without return types