Calling a ComplexType as a function in PySimpleSoap

Question

Given the following PHP which returns a valid Soap/XML Response:

$params = new StdClass();
$params->subRequest = new StdClass();
$params->subRequest->endCSN = "0212341234";
$client = new SoapClient($WSDL);
$response = $client->qualifyProduct($params);

I'm trying to implement the connection to this web service in Python, but I'm not getting very far - running into errors (I tried in PHP just as a sanity check).

I've so far tried a number of possible options that seem to make sense in my head including:

client = SoapClient(WSDL)
a = type('lambdaobject', (object,), {})()
a.endCSN = "0212341234"
response = client.qualifyProduct(subRequest = a)`

response = client.qualifyProduct({'subRequest':{'endCSN':{'0212121212'}}})

response = client.qualifyProduct(subRequest = {'endCSN':{'0212121212'}})

None of which work - and all give me a PySimpleSoap error like:

ValueError: Invalid Args Structure. Errors: [u"Argument key subRequest not in parameter.

The answer for PySimpleSoap: How to pass a complexType as a function parameter seemed to offer a glimmer of hope, but didn't end up working in my instance.

I do have other functions working with the given WSDL, but none with a ComplexType for the method defined like this extract where the subRequest and anotherSubRequest types are defined in another .xsd file:

<xsd:complexType name="QualifyProductRequest">
    <xsd:sequence>
        <xsd:choice>
            <xsd:element name="subRequest" type="wsg:subRequest">
                <xsd:annotation>
                    <xsd:documentation xml:lang="en">A complex type capturing required data for a qualification</xsd:documentation>
                </xsd:annotation>
            </xsd:element>
            <xsd:element name="anotherSubRequest" type="wsg:anotherSubRequest">
                <xsd:annotation>
                    <xsd:documentation xml:lang="en">A complex type capturing required data for a different qualification</xsd:documentation>
                </xsd:annotation>
            </xsd:element>
        <! -- SNIPPED -->
        </xsd:choice>
    </xsd:sequence>
</xsd:complexType>