Forum Discussion
Up front: I'm very new to the SDK. My efforts so far have only focused on querying the device and reading state. I haven't practiced much in the realm of creating or modifying objects.
The pool members are a sub-collection under the pool. You can get the sub-collection:
pool_a.members_s.get_collection()
which will return a list of member objects. It looks like you're trying to pass just a string, where the collection of members is actually a list of member objects. Rather than botch the nomenclature, I found a decent starting example in the docs. Look about half-way down in the coding example on this link for an example of creating new pool members:
Managing LTM Pools and Members via the F5 SDK
Sorry I can't give you a more concrete example but hopefully this will help give you a start until someone with more experience on the SDK can fill in any other details.