How to use the grafeas.grafeas_v1.gapic.enums.DiscoveryOccurrence.AnalysisStatus.PENDING function in grafeas

AND noteId="PACKAGE_VULNERABILITY"'.format(resource_url)
        # [END containeranalysis_poll_discovery_occurrence_finished]
        # The above filter isn't testable, since it looks for occurrences in a
        # locked down project fall back to a more permissive filter for testing
        filter_str = 'kind="DISCOVERY" AND resourceUrl="{}"'\
            .format(resource_url)
        # [START containeranalysis_poll_discovery_occurrence_finished]
        result = grafeas_client.list_occurrences(project_name, filter_str)
        # only one occurrence should ever be returned by ListOccurrences
        # and the given filter
        for item in result:
            discovery_occurrence = item
        if time.time() > deadline:
            raise RuntimeError('timeout while retrieving discovery occurrence')

    status = DiscoveryOccurrence.AnalysisStatus.PENDING
    while status != DiscoveryOccurrence.AnalysisStatus.FINISHED_UNSUPPORTED \
            and status != DiscoveryOccurrence.AnalysisStatus.FINISHED_FAILED \
            and status != DiscoveryOccurrence.AnalysisStatus.FINISHED_SUCCESS:
        time.sleep(1)
        updated = grafeas_client.get_occurrence(discovery_occurrence.name)
        status = updated.discovery.analysis_status
        if time.time() > deadline:
            raise RuntimeError('timeout while waiting for terminal state')
    return discovery_occurrence
# [END containeranalysis_poll_discovery_occurrence_finished]

while discovery_occurrence is None:
        time.sleep(1)
        sys.stdout.write(".")
        resource_url = get_resource_url(resource_url)
        filter_str = 'resourceUrl="{}" \
                      AND noteProjectId="goog-analysis" \
                      AND noteId="PACKAGE_VULNERABILITY"'.format(resource_url)
        result = grafeas_client.list_occurrences(project_name, filter_str)
        # only one occurrence should ever be returned by ListOccurrences
        # and the given filter
        for item in result:
            discovery_occurrence = item
        if time.time() > deadline:
            raise RuntimeError('timeout while retrieving discovery occurrence')

    status = DiscoveryOccurrence.AnalysisStatus.PENDING
    while status != DiscoveryOccurrence.AnalysisStatus.FINISHED_UNSUPPORTED \
            and status != DiscoveryOccurrence.AnalysisStatus.FINISHED_FAILED \
            and status != DiscoveryOccurrence.AnalysisStatus.FINISHED_SUCCESS:
        time.sleep(1)
        sys.stdout.write(".")
        updated = grafeas_client.get_occurrence(discovery_occurrence.name)
        status = updated.discovery.analysis_status
        if time.time() > deadline:
            raise RuntimeError('timeout while waiting for terminal state')
    print("")
    return discovery_occurrence