def _annotation_stmt(self, stmt: Statement, sctx: SchemaContext) -> None:
        """Handle annotation statement."""
        if not sctx.schema_data.if_features(stmt, sctx.text_mid):
            return
        dst = stmt.find1("description")
        self.annotations[(stmt.argument, sctx.default_ns)] = Annotation(
            DataType._resolve_type(stmt.find1("type", required=True), sctx),
            dst.argument if dst else None)
Handle annotation statement.