Added missing use of packaging.version
@@ -309,7 +309,7 @@ class BoxWhiskerPlot(CompositeElementPlot, ColorbarPlot, LegendPlot):
factors = list(unique_iterator(factors))
if self.show_legend:
- legend_prop = 'legend_field' if bokeh_version >= '1.3.5' else 'legend'
+ legend_prop = 'legend_field' if bokeh_version >= LooseVersion('1.3.5') else 'legend'
vbar_map[legend_prop] = cdim.name
return data, mapping, style
