'''<?Xml version="1.0" encoding="UTF-8"?> <!DOCTYPE phox-response SYSTEM "value"> <!-- server version : 999999999

-->
<phox-response sessionid="9999999999" buildnumber="9999999999999" date="05.04.2021 09:55:42">
<content>
<o n="">
<s n="results">
<o n="results">
<f t="I" v="1278489247" n="objectId"/>
<f t="S" v="Message" n="messageText"/>
<f t="I" v="1278489248" n="id"/>
<f t="L" v="59164260" n="timestamp"/>
<f t="D" v="03.04.2021 11:57:20" n="processDate"/>
<f t="S" v="HEADER" n="header"/>
<f t="I" v="4" n="state"/>
<f t="I" v="51" n="sendType"/>
<f t="I" v="2" n="sendMethod"/>
<f t="D" v="02.04.2021 12:00:38" n="createDate"/>
<f t="S" v="mail1,mail2" n="address"/>
<r n="lab" i="644249461"/>
</o>
<o n="results">
<f t="I" v="1278339695" n="objectId"/>
<f t="S" v="Message" n="messageText"/>
<f t="I" v="1278339696" n="id"/>
<f t="L" v="59164259" n="timestamp"/>
<f t="D" v="03.04.2021 11:57:20" n="processDate"/>
<f t="S" v="HEADER" n="header"/>
<f t="I" v="4" n="state"/>
<f t="I" v="51" n="sendType"/>
<f t="I" v="2" n="sendMethod"/>
<f t="D" v="02.04.2021 10:36:17" n="createDate"/>
<f t="S" v="mail1,mail2" n="address"/>
<r n="lab" i="644249461"/>
</o>
</s>
</o>
</content>
</phox-response>'''

Дотер...

?

библиотека lxml с помощью XPath ищет узлы по значению их атрибутов tree.xpath('//f[@n="objectId"]')[0].attrib.get('v') и остальные по аналогии

Сделал циклом