Transform input `X`.

        Note: all imputations should have a `fit_transform` method,
        but only some (like IterativeImputer) also support inductive mode
        using `fit` or `fit_transform` on `X_train` and then `transform`
        on new `X_test`.

def transform(self, X, y=None):
        """
        Transform input `X`.

        Note: all imputations should have a `fit_transform` method,
        but only some (like IterativeImputer) also support inductive mode
        using `fit` or `fit_transform` on `X_train` and then `transform`
        on new `X_test`.
        """
        raise ValueError(
            "%s.transform not implemented! This imputation algorithm likely "
            "doesn't support inductive mode. Only %s.fit_transform is "
            "supported at this time." % (
                self.__class__.__name__, self.__class__.__name__))