code: def plot_options(cls, obj, percent_size):
          
          from .plot import MPLPlot
          factor = percent_size / 100.0
          obj = obj.last if isinstance(obj, HoloMap) else obj
          options = Store.lookup_options(cls.backend, obj, 'plot').options
          fig_size = options.get('fig_size', MPLPlot.fig_size)*factor
  
          return dict({'fig_size':fig_size},
                      **MPLPlot.lookup_options(obj, 'plot').options)
docs: Given a holoviews object and a percentage size, apply heuristics
          to compute a suitable figure size. For instance, scaling layouts
          and grids linearly can result in unwieldy figure sizes when there
          are a large number of elements. As ad hoc heuristics are used,
          this functionality is kept separate from the plotting classes
          themselves.
  
          Used by the IPython Notebook display hooks and the save
          utility. Note that this can be overridden explicitly per object
          using the fig_size and size plot options.