def METHOD_NAME(self):
    errorbars = ErrorBars([(0, 0, 0.1, 0.2, 1), (0, 1, 0.2, 0.4, 4), (0, 2, 0.6, 1.2, 8)],
                          vdims=['y', 'perr', 'nerr', 'line_width']).opts(linewidth='line_width')
    plot = mpl_renderer.get_plot(errorbars)
    artist = plot.handles['artist']
    self.assertEqual(artist.get_linewidths(), [1, 4, 8])