'Perform request(s) to obtain all results from \'api_name\'.
This method will make requests to the aggregated \'api_name\' until
all results are received.  It will then, through a helper function,
combine all results and return a single \'items\' dictionary.
:param    api_name: Name of API to call. Consult API docs
for valid names.
:type     api_name: ``str``
:return:  dict in the format of the API response.
format: { \'items\': {\'key\': {api_name: []}} }
ex: { \'items\': {\'zones/us-central1-a\': {disks: []}} }
:rtype:   ``dict``'

def request_aggregated_items(self, api_name):

    request_path = ('/aggregated/%s' % api_name)
    api_responses = []
    params = {'maxResults': 500}
    more_results = True
    while more_results:
        self.gce_params = params
        response = self.request(request_path, method='GET').object
        if ('items' in response):
            api_responses.append(response)
        more_results = ('pageToken' in params)
    return self._merge_response_items(api_name, api_responses)
