Initialialize for chart rendering

def _get_opts_seaborn(self, opts, style):
        """
        Initialialize for chart rendering
        """
        if opts is None:
            if self.chart_opts is None:
                opts = {}
            else:
                opts = self.chart_opts
        if style is None:
            if self.chart_style is None:
                style = self.chart_style
            else:
                style = {}
        return opts, style