docs: void addToOutputVar(PyExpr pyExpr) {
      boolean isList = pyExpr instanceof PyListExpr;
      if (isList && !getOutputVarIsInited()) {
        appendLine(getOutputVarName(), " = ", pyExpr.getText());
      } else {
        initOutputVarIfNecessary();
        String function = isList ? ".extend(" : ".append(";
        appendLine(getOutputVarName(), function, pyExpr.getText(), ")");
      }
      setOutputVarInited();
    }