def request_is_rebuild(spec_obj):
    """Returns True if request is for a rebuild.

    :param spec_obj: An objects.RequestSpec to examine (or None).
    """
    if not spec_obj:
        return False
    if 'scheduler_hints' not in spec_obj:
        return False
    check_type = spec_obj.scheduler_hints.get('_nova_check_type')
    return check_type == ['rebuild']
