public LinkedHashMap<String, String> getFunctionAttributes() {
    LinkedHashMap<String, String> result = new LinkedHashMap<>();
    for (int i = 0; i + 1 < this.functionAttributesKeyValueList.size(); i += 2) {
      result.put(
          this.functionAttributesKeyValueList.get(i),
          this.functionAttributesKeyValueList.get(i + 1));
    }
    return result;
  }
example: select udf(a, b, udf(c)) from root.sg.d;

<p>3 expressions [root.sg.d.a, root.sg.d.b, udf(root.sg.d.c)] will be in this field.
iotdb-core/node-commons/src/main/java/org/apache/iotdb/commons/schema/view/viewExpression/multi/FunctionViewExpression.java