figure items not constrained in their physical placement figure relative positions maintained by explicit links the location of the next item (see figure then the relative position of each item can be expressed by simply following the link from one item to the next it is important to note that the location of the first item of the list must be explicitly specified once we know where the first item isthe first item can tell us where the second isand so on the external reference is often referred to as the head of the list similarlythe last item needs to know that there is no next item the node class the basic building block for the linked list implementation is the node each node object must hold at least two pieces of information firstthe node must contain the list item itself we will call this the data field of the node in additioneach node must hold reference to the next node to construct nodeyou need to supply the initial data value for the node evaluating the assignment statement below will yield node object containing the value (see figure you should note that we will typically represent node object as shown in figure the node class also includes the usual methods to access and modify the data and the next reference class nodedef __init__(selfinit_data)self data init_data self next none def get_data(self)return self data implementing an unordered listlinked lists