'Insert a title on top of the summary table. If a string is provided
in the title argument, that string is printed. If no title string is
provided but a results instance is provided, statsmodels attempts
to construct a useful title automatically.'

def add_title(self, title=None, results=None):

    if isinstance(title, string_types):
        self.title = title
    else:
        try:
            model = results.model.__class__.__name__
            if (model in _model_types):
                model = _model_types[model]
            self.title = ('Results:    ' + model)
        except:
            self.title = ''
