'Retrieves the subscriptions in the specified topic.
topic_name:
Name of the topic.'

def list_subscriptions(self, topic_name):

    _validate_not_none('topic_name', topic_name)
    request = HTTPRequest()
    request.method = 'GET'
    request.host = self._get_host()
    request.path = (('/' + _str(topic_name)) + '/subscriptions/')
    (request.path, request.query) = self._httpclient._update_request_uri_query(request)
    request.headers = self._update_service_bus_header(request)
    response = self._perform_request(request)
    return _ETreeXmlToObject.convert_response_to_feeds(response, _convert_etree_element_to_subscription)
