class unsortedpriorityqueue(priorityqueuebase)base class defines item """ min-oriented priority queue implemented with an unsorted list "" nonpublic utility def find min(self) """return position of item with minimum key ""is empty inherited from base class if self is empty) raise emptypriority queue is empty small self data first walk self data after(small while walk is not none if walk elementsmall element) small walk walk self data after(walk return small def init (self) """create new empty priority queue "" self data positionallist def len (self) """return the number of items in the priority queue "" return len(self data def add(selfkeyvalue) """add key-value pair "" self data add last(self item(keyvalue) def min(self) """return but do not remove ( ,vtuple with minimum key "" self find min item element return (item keyitem value def remove min(self) """remove and return ( ,vtuple with minimum key "" self find min item self data delete( return (item keyitem valuecode fragment an implementation of priority queue using an unsorted list the parent class priorityqueuebase is given in code fragment and the positionallist class is from section