var math = subclasses.Classes.Where(x => x.Id.Equals(Constants.Classes.Math.ToString())).FirstOrDefault= null) subclasses.Classes.Remove(math);
var chem= subclasses.Classes.Where(x => x.Id.Equals(Constants.Classes.Chem.ToString= null) subclasses.Classes.Rem
__subclasses__()'{0.__class__.__mro__[1].__subclasses__()}'.format('a')AttributeError: type object 'object' has no attribute '__subclasses__subclasses__}'.format('a')'<