def get_storage(clear=False):
    """helper function to get annotation storage on the portal

    :param clear: If true is passed in, annotations will be cleared
    :returns: portal annotations
    :rtype: IAnnotations

    """
    portal = getUtility(ISiteRoot)
    annotations = IAnnotations(portal)
    if ANNOTATION_KEY not in annotations or clear:
        annotations[ANNOTATION_KEY] = OOBTree()
    return annotations[ANNOTATION_KEY]