Check if xticks and yticks are set

def _get_ticks(self, opts):
        """
        Check if xticks and yticks are set
        """
        opts, _ = self._get_opts(opts, None)
        if "xticks" not in opts:
            if "xticks" not in self.chart_opts:
                self.err(self.dlinear_,
                         "Please set the xticks option for this chart to work")
                return
            else:
                xticks = self.chart_opts["xticks"]
        else:
            xticks = opts["xticks"]
        if "yticks" not in opts:
            if "yticks"not in self.chart_opts:
                self.err(self.dlinear_,
                         "Please set the yticks option for this chart to work")
                return
            else:
                yticks = self.chart_opts["yticks"]
        else:
            yticks = opts["yticks"]
        return xticks, yticks