def _handle_properties(self, stmt: Statement, sctx: SchemaContext) -> None:
        """Handle **enum** statements."""
        nextval = 0
        for est in stmt.find_all("enum"):
            if not sctx.schema_data.if_features(est, sctx.text_mid):
                continue
            label = est.argument
            vst = est.find1("value")
            if vst:
                val = int(vst.argument)
                self.enum[label] = val
                if val > nextval:
                    nextval = val
            else:
                self.enum[label] = nextval
            nextval += 1