code: def test_curve_style_mapping_constant_value_dimensions(self):
      vdims = ["y", "num", "cat"]
      ndoverlay = NdOverlay(
          {
              0: Curve([(0, 1, 0, "A"), (1, 0, 0, "A")], vdims=vdims),
              1: Curve([(0, 1, 0, "B"), (1, 1, 0, "B")], vdims=vdims),
              2: Curve([(0, 1, 1, "A"), (1, 2, 1, "A")], vdims=vdims),
              3: Curve([(0, 1, 1, "B"), (1, 3, 1, "B")], vdims=vdims),
          }
      ).opts(
          {
              "Curve": dict(
                  color=dim("num").categorize({0: "red", 1: "blue"}),
                  linestyle=dim("cat").categorize(
                      {"A": "-.", "B": "-"}
                  ),
              )
          }
      )
      plot = mpl_renderer.get_plot(ndoverlay)
      for k, sp in plot.subplots.items():
          artist = sp.handles["artist"]
          color = artist.get_color()
          if ndoverlay[k].iloc[0, 2] == 0:
              self.assertEqual(color, "red")
          else:
              self.assertEqual(color, "blue")
          linestyle = artist.get_linestyle()
          if ndoverlay[k].iloc[0, 3] == "A":
              self.assertEqual(linestyle, "-.")
          else:
              self.assertEqual(linestyle, "-")
  
imports: import datetime
  import numpy
  import pandas
  import pytest
  from holoviews.core.options import AbbreviatedException
  from holoviews.core.overlay import NdOverlay
  from holoviews.element import Curve
  from holoviews.util.transform import dim
  from .test_plot import TestMPLPlot, mpl_renderer
label_desc: Use image node_id 22 for calling the TestCurvePlot obj's underlying member method code with example usage: obj.test_curve_style_mapping_constant_value_dimensions() without return types