method to sanitize model parameters

        Parameters
        ---------
        None

        Returns
        -------
        None

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

        Parameters
        ---------
        None

        Returns
        -------
        None
        """
        # fit_intercep
        if not isinstance(self.fit_intercept, bool):
            raise ValueError('fit_intercept must be type bool, but found {}'\
                             .format(self.fit_intercept.__class__))

        # terms
        if (self.terms is not 'auto') and not (isinstance(self.terms, (TermList, Term, type(None)))):
            raise ValueError('terms must be a TermList, but found '\
                             'terms = {}'.format(self.terms))

        # max_iter
        self.max_iter = check_param(self.max_iter, param_name='max_iter',
                                    dtype='int', constraint='>=1',
                                    iterable=False)

        # distribution
        if not ((self.distribution in DISTRIBUTIONS)
                or isinstance(self.distribution, Distribution)):
            raise ValueError('unsupported distribution {}'.format(self.distribution))
        if self.distribution in DISTRIBUTIONS:
            self.distribution = DISTRIBUTIONS[self.distribution]()

        # link
        if not ((self.link in LINKS) or isinstance(self.link, Link)):
            raise ValueError('unsupported link {}'.format(self.link))
        if self.link in LINKS:
            self.link = LINKS[self.link]()

        # callbacks
        if not isiterable(self.callbacks):
            raise ValueError('Callbacks must be iterable, but found {}'\
                             .format(self.callbacks))

        if not all([c in CALLBACKS or
                    isinstance(c, CallBack) for c in self.callbacks]):
            raise ValueError('unsupported callback(s) {}'.format(self.callbacks))
        callbacks = list(self.callbacks)
        for i, c in enumerate(self.callbacks):
            if c in CALLBACKS:
                callbacks[i] = CALLBACKS[c]()
        self.callbacks = [validate_callback(c) for c in callbacks]