def heuristicAnnotationMatch(a1, a2):
    """takes two annotations and returns 1 if exact match,
    0 if partial match (types match), -1 if no match

    """
    if a1.db_key == a2.db_key:
        if a1.db_value == a2.db_value:
            return 1
        else:
            return 0
    return -1