/// <summary>
 /// Returns true if the set contains no types, only the object or unknown
 /// types, or None.
 /// </summary>
 public static bool IsObjectOrUnknownOrNone(this IAnalysisSet res)
 => res.IsObjectOrUnknown() || res.All(v => v.TypeId == BuiltinTypeId.NoneType);
 public static bool IsUnknown(this IAnalysisSet res)
 {
     return(res == null ||
            res.Count == 0 ||
            res.All(v => v.TypeId == BuiltinTypeId.Unknown && v.MemberType == PythonMemberType.Unknown));
 }