code: def test_items(self) -> None:
      source = ColumnDataSource(
          data=dict(foo=[10, 10, 20, 30, 20, 30, 40])
      )
      renderer = GlyphRenderer(data_source=source)
      legend = Legend(items=[])
      bpl._handle_legend_group("foo", legend, renderer)
      assert len(legend.items) == 4
      assert legend.items[0].label == value("10")
      assert legend.items[0].renderers == [renderer]
      assert legend.items[0].index == 0
  
      assert legend.items[1].label == value("20")
      assert legend.items[1].renderers == [renderer]
      assert legend.items[1].index == 2
  
      assert legend.items[2].label == value("30")
      assert legend.items[2].renderers == [renderer]
      assert legend.items[2].index == 3
  
      assert legend.items[3].label == value("40")
      assert legend.items[3].renderers == [renderer]
      assert legend.items[3].index == 6
  
imports: from __future__ import annotations
  import pytest
  import itertools
  from bokeh.core.properties import field, value
  from bokeh.models import ColumnDataSource, GlyphRenderer, Legend, LegendItem
  from bokeh.plotting import figure
  import bokeh.plotting._legends
label_desc: Use image node_id 3 for calling the Test__handle_legend_group obj's underlying member method code with example usage: obj.test_items() without return types