advanced_iterators: Added the function len_slice, which determines the length of a slice without having to apply it. If the slice does not have a value for its stop point and a length is not specified, it will raise an exception as the length cannot be determined from that information.
advanced_iterators: Added the function len_slice, which determines the length of a slice without having to apply it. If the slice does not have a value for its stop point and a length is not specified, it will raise an exception as the length cannot be determined from that information.

jakirkham/nanshe,nanshe-org/nanshe,DudLab/nanshe,jakirkham/nanshe,nanshe-org/nanshe,DudLab/nanshe