code: def reduce(self, dimensions=[], function=None, spreadfn=None, **kwargs):
          
          kwargs['_method_args'] = (dimensions, function, spreadfn)
          return self.__call__('reduce', **kwargs)
docs: Applies a reduce function to all ViewableElement objects.
  
          See :py:meth:`Dimensioned.opts` and :py:meth:`Apply.__call__`
          for more information.