sequences the node class class nodedef __init__(self,item,next=none)self item item self next next def getitem(self)return self item def getnext(self)return self next def setitem(selfitem)self item item def setnext(self,next)self next next in the node class there are two pieces of informationthe item is reference to value in the listand the next reference which points to the next node in the sequence figure is linked list with three elements added to it there are four nodes in this figure the first node is dummy node having one extra dummy node at the beginning of the sequence eliminates lot of special cases that must be considered when working with the linked list an empty sequence still has dummy node nodes in linked lists are represented as rounded rectangle with two halves the left half of node is reference to the item or value for that node in the sequence the right half is reference to the next node in the sequence or to the special value none if it is the last node in the sequence figure depicts linked list consisting of three pieces of information we keep reference to the first node in the sequence so we can traverse the nodes when necessary the reference to the last node in the list makes it possible to append an item to the list in ( time we also keep track of the number of items so we don' have to count when someone wants to retrieve the list size the table of operations in fig contains the computational complexity of various list operations on the linkedlist datatype presented in this section many fig sample linkedlist object this copy belongs to 'acha