def METHOD_NAME(self):
    from sklearn.model_selection import train_test_split
    self.x_train, self.x_test, self.y_train, self.y_test = train_test_split(
        self._x, self._y, test_size=0.20, random_state=42
    )
    self.x_train, self.x_valid, self.y_train, self.y_valid = train_test_split(
        self.x_train, self.y_train, test_size=0.40, random_state=42
    )