code: def _augment_stmt(self, stmt: Statement, sctx: SchemaContext) -> None:
          
          if not sctx.schema_data.if_features(stmt, sctx.text_mid):
              return
          path = sctx.schema_data.sni2route(stmt.argument, sctx)
          target = self.get_schema_descendant(path)
          if stmt.find1("when"):
              gr = GroupNode()
              target._add_child(gr)
              target = gr
          target._handle_substatements(stmt, sctx)
docs: Handle **augment** statement.