method to validate and prepare data-dependent parameters

        Parameters
        ---------
        X : array-like
            Input dataset

        verbose : bool
            whether to show warnings

        Returns
        -------
        None

def compile(self, X, verbose=False):
        """method to validate and prepare data-dependent parameters

        Parameters
        ---------
        X : array-like
            Input dataset

        verbose : bool
            whether to show warnings

        Returns
        -------
        None
        """
        super(FactorTerm, self).compile(X)

        self.n_splines = len(np.unique(X[:, self.feature]))
        self.edge_knots_ = gen_edge_knots(X[:, self.feature],
                                          self.dtype,
                                          verbose=verbose)
        return self