code: def test_overlay_xlabel_override(self):
      overlay = (Curve(range(10)) * Curve(range(10))).opts(
          xlabel="custom x-label"
      )
      plot = bokeh_renderer.get_plot(overlay).state
      self.assertEqual(plot.xaxis[0].axis_label, "custom x-label")
  
imports: import numpy
  import panel
  from bokeh.models import FactorRange, FixedTicker, HoverTool, Range1d, Span
  from holoviews.core import DynamicMap, HoloMap, NdOverlay, Overlay
  from holoviews.element import Bars, Box, Curve, ErrorBars, HLine, Points, Scatter, Text, VLine
  from holoviews.plotting.bokeh.util import property_to_dict
  from holoviews.streams import Stream, Tap
  from holoviews.util import Dynamic
  from ...utils import LoggingComparisonTestCase
  from .test_plot import TestBokehPlot, bokeh_renderer
label_desc: Use image node_id 11 for calling the TestOverlayPlot obj's underlying member method code with example usage: obj.test_overlay_xlabel_override() without return types