code: def test_server_on_change_round_trip(
      self, bokeh_server_page: BokehServerPage
  ) -> None:
      slider = DatetimeRangeSlider(
          start=start, end=end, value=value, width=300
      )
  
      def modify_doc(doc):
          source = ColumnDataSource(
              dict(x=[1, 2], y=[1, 1], val=["a", "b"])
          )
          plot = Plot(
              height=400,
              width=400,
              x_range=Range1d(0, 1),
              y_range=Range1d(0, 1),
              min_border=0,
          )
          plot.add_glyph(source, Scatter(x="x", y="y", size=20))
          plot.tags.append(
              CustomJS(
                  name="custom-action",
                  args=dict(s=source),
                  code=RECORD("data", "s.data"),
              )
          )
  
          def cb(attr, old, new):
              source.data["val"] = [
                  slider.value_as_datetime[0].isoformat(),
                  slider.value_as_datetime[1].isoformat(),
              ]
  
          slider.on_change("value", cb)
          doc.add_root(column(slider, plot))
  
      page = bokeh_server_page(modify_doc)
  
      drag_range_slider(page.driver, slider, "lower", 5)
  
      page.eval_custom_action()
      results = page.results
      new = results["data"]["val"]
      assert new[0] > "2022-02-01"
  
      drag_range_slider(page.driver, slider, "upper", -5)
  
      page.eval_custom_action()
      results = page.results
      new = results["data"]["val"]
      assert new[1] < "2022-03-25"
  
file_path: bokeh/tests/integration/widgets/test_datetime_range_slider.py
imports: from __future__ import annotations
  import pytest
  from datetime import datetime, timedelta
  from time import sleep
  from bokeh.layouts import column
  from bokeh.models import ColumnDataSource, CustomJS, DatetimeRangeSlider, Plot, Range1d, Scatter
  from tests.support.plugins.project import BokehModelPage, BokehServerPage
  from tests.support.util.selenium import RECORD, drag_range_slider, find_elements_for, get_slider_bar_color, get_slider_title_text, get_slider_title_value
label_desc: Use image node_id 5 for calling the Test_DatetimeRangeSlider obj's underlying member method code with example usage: obj.test_server_on_change_round_trip(bokeh_server_page) without return types