ithout repetitions that are organized in a particular order and accepts frequent insertions and removals at any point of the sequence during iterations.</p>

<p>Stores each value of the set by mapping it to its successor.
Therefore, all values are stored as mapped keys.
The only exception is the last value that provides no successor.
Each instance maps two special values, one to the first value of the sequence and other to the last value.
Instances behave like linked lists that does not allow repeated value