code: def _fontsize(self, key, label='fontsize', common=True):
          
          size = super(BokehPlot, self)._fontsize(key, label, common)
          return {k: v if isinstance(v, basestring) else '%spt' % v
                  for k, v in size.items()}
docs: Converts integer fontsizes to a string specifying
          fontsize in pt.