code: def test_LabelSet() -> None:
      label_set = LabelSet()
      assert label_set.level == "annotation"
      assert label_set.x == field("x")
      assert label_set.y == field("y")
      assert label_set.x_units == "data"
      assert label_set.y_units == "data"
      assert label_set.text == field("text")
      assert label_set.angle == 0
      assert label_set.angle_units == "rad"
      assert label_set.x_offset == 0
      assert label_set.y_offset == 0
      assert label_set.x_range_name == "default"
      assert label_set.y_range_name == "default"
      assert isinstance(label_set.source, ColumnDataSource)
      assert label_set.source.data == {}
      check_text_properties(label_set)
      check_fill_properties(label_set, "background_", None, 1.0)
      check_line_properties(label_set, "border_", None, 1.0, 1.0)
      check_properties_existence(
          label_set,
          [
              *ANNOTATION,
              "x",
              "y",
              "x_units",
              "y_units",
              "text",
              "angle",
              "angle_units",
              "x_offset",
              "y_offset",
              "source",
          ],
          TEXT,
          ANGLE,
          prefix("border_", LINE),
          prefix("background_", FILL),
      )
  
imports: from __future__ import annotations
  import pytest
  from datetime import datetime
  from unittest import mock
  from bokeh.core.properties import field, value
  from bokeh.core.validation import check_integrity, process_validation_issues
  from bokeh.models import Arrow, ArrowHead, Band, BoxAnnotation, ColorBar, ColumnDataSource, GlyphRenderer, Label, LabelSet, Legend, LegendItem, LinearColorMapper, Node, PolyAnnotation, Slope, Span, Title, Whisker
  from bokeh.util.serialization import convert_datetime_type
  from _util_models import ABOVE_FILL, ABOVE_HATCH, ANGLE, BELOW_FILL, BELOW_HATCH, FILL, HATCH, HOVER_FILL, HOVER_HATCH, HOVER_LINE, LINE, TEXT, check_fill_properties, check_hatch_properties, check_line_properties, check_properties_existence, check_text_properties, prefix
label_desc: Use image node_id 10 for calling a global function with example usage: test_LabelSet() without return types