code: def test_op_ndoverlay_value(self):
      markers = ["circle", "triangle"]
      overlay = NdOverlay(
          {
              marker: Points(np.arange(i))
              for i, marker in enumerate(markers)
          },
          "Marker",
      ).opts("Points", marker="Marker")
      plot = bokeh_renderer.get_plot(overlay)
      for subplot, glyph_type, marker in zip(
          plot.subplots.values(), [Scatter, Scatter], markers
      ):
          self.assertIsInstance(subplot.handles["glyph"], glyph_type)
          self.assertEqual(subplot.handles["glyph"].marker, marker)
  
imports: import datetime
  import numpy
  import pandas
  from bokeh.models import CategoricalColorMapper, FactorRange, LinearColorMapper, Scatter
  from holoviews.core import NdOverlay
  from holoviews.core.options import Cycle
  from holoviews.element import Points
  from holoviews.plotting.bokeh.util import property_to_dict
  from holoviews.streams import Stream
  from ..utils import ParamLogStream
  from .test_plot import TestBokehPlot, bokeh_renderer
label_desc: Use image node_id 51 for calling the TestPointPlot obj's underlying member method code with example usage: obj.test_op_ndoverlay_value() without return types