code: def assert_hline(self, shape, y, yref="y", xdomain=(0, 1)):
      self.assertEqual(shape["type"], "line")
      self.assertEqual(shape["y0"], y)
      self.assertEqual(shape["y1"], y)
      self.assertEqual(shape["yref"], yref)
  
      self.assertEqual(shape["x0"], xdomain[0])
      self.assertEqual(shape["x1"], xdomain[1])
      self.assertEqual(shape["xref"], "paper")
  
imports: import numpy
  from holoviews.element import Bounds, Box, HLine, Path, Rectangles, Segments, Tiles, VLine
  from .test_plot import TestPlotlyPlot
label_desc: Use image node_id 2 for calling the TestVLineHLine obj's underlying member method code with example usage: obj.assert_hline(shape, y, yref, xdomain) without return types