Python zeep how to generate AnyType object?

Question

Python

I use zeep to interact with SOAP API.
One of the methods accepts (xs:int NeedList, xs:string SessionToken, xs:anyType TariffParameters) an object of type AnyType, which obviously is not described in the XSD. In this case, you need to put a lot of nested parameters into the object. All attempts so far ended with the transfer of either an xml string, in the form

<TariffParameters>\&lt;tag\&gt;value\&lt;\tag\&gt;</TariffParameters>

or in the form of structures of type dict

<TariffParameters>{ 'Constructed': '2014-01-01', 'Model': '3251066103',}</TariffParameters>

etc.
The goal is to pass the correct XML format to TariffParameters. How to do it?