This does not do what it is supposed to do, or it is misused in the ansible module.

[VortexUK]

hpe3par_python_sdk/hpe3par_sdk/client.py

Line 1585 in 874bc32

hosts = self.client.queryHost(iqns, wwns)['members']

This will return wwn's that exist on the storage, regardless of if they are already used in another host or not. Which means when you are trying to add WWNs to an existing host, ansible will complain that "they are already part of another host" when they are not. Add something like this:

hosts = self.client.queryHost(iqns, wwns)['members']
        for host in [x for x in hosts if x.get('name',None)]:
            host_list.append(Host(host))
        return host_list

Or fix the ansible module:
https://github.com/HewlettPackard/hpe3par_ansible_module/blob/master/Modules/hpe3par_host.py#L622-L627

This should become:

host_list = client_obj.queryHost(wwns=wwn_list)
for host_obj in host_list:
    host_name_3par = host_obj.name
    if host_name_3par:
        if host_name == host_name_3par:
            wwn_same_host.append(wwn)
        else:
            wwn_other_host.append(wwn)