7. (3 pts) Write an algorithm for the implementation of the method swap_ends() of the DLLDeque data structure below. DLLDeque implements the Deque interface using a doubly-linked list. The method swap_ends() swaps the node (not just the data) at the head of the list with the node at the tail of the list. 1 from Interfaces import Deque 2 3 class DLLDeque(Deque): 4 class Node: s def __init__(self,x: object): 6 self.x = x 7 self.next = None & self.prev = None 9 10 def_init__(self): 11 self.dummy - DLList. Node(None) 12 self.dummy.next = dummy 13 self.dummy.prev = dummy 14 self.n = 0 15 return 16 17... 18 10def swap_ends(self): 20 # todo 21 return