code: def test_distribution_composite_empty_not_filled(self):
      dist = Distribution([]).opts(filled=False)
      curve = Compositor.collapse_element(dist, backend="matplotlib")
      assert isinstance(curve, Curve)
      assert curve.vdims == [Dimension(("Value_density", "Density"))]
  
imports: import numpy
  import pandas
  import pytest
  from holoviews.core.dimension import Dimension
  from holoviews.core.options import Compositor, Store
  from holoviews.element import Area, Bivariate, Contours, Curve, Distribution, Image, Points, Polygons
label_desc: Use image node_id 7 for calling the TestStatisticalCompositor obj's underlying member method code with example usage: obj.test_distribution_composite_empty_not_filled() without return types