def getConstrainTypesMode():
    """
        Find out if add-restrictions are enabled. Returns 0 if they are
        disabled (the type's default FTI-set allowable types is in effect),
        1 if they are enabled (only a selected subset if allowed types will be
        available), and -1 if the allowed types should be acquired from the
        parent. Note that in this case, if the parent portal type is not the
        same as the portal type of this object, fall back on the default (same
        as 0)
        """
