def validate(self):
        """
        Error check model params.

        :raises TypeError: Throws TypeError if validation fails.

        """
        if self.nregions is None:
            raise TypeError("neutral regions cannot be None")
        if self.sregions is None:
            raise TypeError("selected regions cannot be None")
        if self.recregions is None:
            raise TypeError("recombination regions cannot be None")
        if self.demography is None:
            raise TypeError("demography cannot be None")
        if self.prune_selected is None:
            raise TypeError("prune_selected cannot be None")
        if self.gvalue is None:
            raise TypeError("gvalue cannot be None")
        if self.rates is None:
            raise TypeError("rates cannot be None")