code: def test_violin_empty(self):
      violin = Violin([])
      plot = bokeh_renderer.get_plot(violin)
      patch_source = plot.handles["patches_1_source"]
      self.assertEqual(patch_source.data["xs"], [[]])
      self.assertEqual(patch_source.data["ys"], [np.array([])])
  
imports: from unittest import SkipTest
  import numpy
  from bokeh.models import CategoricalColorMapper, LinearColorMapper
  from holoviews.element import Violin
  from holoviews.operation.stats import univariate_kde
  from holoviews.plotting.bokeh.util import property_to_dict
  from holoviews.util.transform import dim
  from .test_plot import TestBokehPlot, bokeh_renderer
label_desc: Use image node_id 7 for calling the TestBokehViolinPlot obj's underlying member method code with example usage: obj.test_violin_empty() without return types