Prepare/modify data for plotting

def setup_data(self):
        """
        Prepare/modify data for plotting
        """
        data = self.data
        if len(data) == 0:
            return type(data)()

        data = self.geom.setup_data(data)

        check_required_aesthetics(
            self.geom.REQUIRED_AES,
            set(data.columns) | set(self.geom.aes_params),
            self.geom.__class__.__name__)

        self.data = data