linked_list.py

class Node:
    def __init__(self, value):
        self.value = value
        self.next = None
        self.previous = None


class LinkedList:
    def __init__(self):
        self.head = None
        self.tail = None

    def push_head(self, value):
        new_node = Node(value)
        
        if self.head is None:
            self.head = new_node
            self.tail = new_node
        else:
            new_node.next = self.head
            self.head.previous = new_node
            self.head = new_node
        
        return new_node

    def pop_tail(self):
       
        if self.tail is None:
            raise IndexError("pop_tail from empty linked list")
        
        value = self.tail.value
        
        if self.head == self.tail:
            self.head = None
            self.tail = None
        else:
            self.tail = self.tail.previous
            self.tail.next = None
        
        return value

    def remove(self, node):
        if node is None:
            raise ValueError("Cannot remove None node")
        
        if node == self.head == self.tail:
            self.head = None
            self.tail = None
        elif node == self.head:
            self.head = node.next
            self.head.previous = None
        elif node == self.tail:
            self.tail = node.previous
            self.tail.next = None
        else:
            node.previous.next = node.next
            node.next.previous = node.previous