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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def apply_to_model(self, model):
        ''' Apply this theme to a model.

        .. warning::
            Typically, don't call this method directly. Instead, set the theme
            on the :class:`~bokeh.document.Document` the model is a part of.

        '''
        model.apply_theme(self._for_class(model.__class__))

        # a little paranoia because it would be Bad(tm) to mess
        # this up... would be nicer if python had a way to freeze
        # the dict.
        if len(_empty_dict) > 0:
            raise RuntimeError("Somebody put stuff in _empty_dict")