method to sanitize model parameters

        Parameters
        ---------
        None

        Returns
        -------
        None

def _validate_arguments(self):
        """method to sanitize model parameters

        Parameters
        ---------
        None

        Returns
        -------
        None
        """
        super(SplineTerm, self)._validate_arguments()

        if self.basis not in self._bases:
            raise ValueError("basis must be one of {}, "\
                             "but found: {}".format(self._bases, self.basis))

        # n_splines
        self.n_splines = check_param(self.n_splines, param_name='n_splines',
                                     dtype='int', constraint='>= 0')

        # spline_order
        self.spline_order = check_param(self.spline_order,
                                        param_name='spline_order',
                                        dtype='int', constraint='>= 0')

        # n_splines + spline_order
        if not self.n_splines > self.spline_order:
            raise ValueError('n_splines must be > spline_order. '\
                             'found: n_splines = {} and spline_order = {}'\
                             .format(self.n_splines, self.spline_order))

        # by
        if self.by is not None:
            self.by = check_param(self.by,
                                  param_name='by',
                                  dtype='int', constraint='>= 0')

        return self