Drop the maximum dose and related response values.

def drop_dose(self):
        """
        Drop the maximum dose and related response values.
        """
        doses = np.array(self.individual_doses)
        responses = np.array(self.responses)
        mask = doses != doses.max()
        self.individual_doses = doses[mask].tolist()
        self.responses = responses[mask].tolist()
        self.set_summary_data()
        self._validate()