[SMN][SDK] topic_attributes method doesn't work properly

[vladimirhasko]

topic_attributes method is a list/generator whle documentation represents it as object

https://docs.otc.t-systems.com/simple-message-notification/api-ref/apis/topic_operations/querying_a_topic_policy.html

with the provided response I cannot get real data from it

>>> conn.smn.topic_attributes("urn:smn:eu-de:c074736b3da440988ef76ab6a0e57244:scenario24-e0326275da1af852291fa5e11864a856topic", name="access_policy")
urn:smn:eu-de:c074736b3da440988ef76ab6a0e57244:scenario24-e0326275da1af852291fa5e11864a856topic
<generator object Resource.list at 0x7f45903faab0>
>>> list(conn.smn.topic_attributes("urn:smn:eu-de:c074736b3da440988ef76ab6a0e57244:scenario24-e0326275da1af852291fa5e11864a856topic", name="access_policy"))
urn:smn:eu-de:c074736b3da440988ef76ab6a0e57244:scenario24-e0326275da1af852291fa5e11864a856topic
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/ubuntu/apimon-tests_custom/.tox/py310/lib/python3.10/site-packages/openstack/resource.py", line 2062, in list
    uri = base_path % params
KeyError: 'topic_urn'