Implementation of Queue using Linked List

queue_using_linked_list.py

class Node(object):
    """
    Fundamental building block of a linked list
    A node consists of a value and the next node location pointer
    """

    def __init__(self, value):
        self.val = value
        self.next = None

class MyQueue(object):
    """
    Queue implementation using LinkedList 
    Queue works in FIFO manner
    """
    def __init__(self):
        self.head = None
        self.tail = None

    def enqueueItem(self, item):
        """
        Add new item to queue - O(1)
        Queuing always happens at tail 
        If Queuing happens at head, dequeuing will require in O(n)
        """
        newNode = Node(item)
        if self.tail:
            self.tail.next = newNode
            self.tail = self.tail.next

        else:
            self.tail = newNode
            self.head = self.tail

    def dequeueItem(self):
        """
        Dequeue item from queue - O(1)
        """

        try:
            self.head = self.head.next
        except AttributeError as error:
            self.head = None

    def peekQueue(self):
        """
        Peek the top value of the queue - O(1)
        """

        try:
            return self.head.val
        except AttributeError as error:
            return None

    def isEmpty(self):
        return self.head == self.tail



# if __name__ == "__main__":
    

#     myQueue = MyQueue()

#     print("Peek QValue", myQueue.peekQueue())

#     myQueue.enqueueItem(9)

#     print("Peek QValue", myQueue.peekQueue())

#     myQueue.enqueueItem(10)

#     print("Peek QValue", myQueue.peekQueue())

#     myQueue.dequeueItem()

#     print("Peek QValue", myQueue.peekQueue())

#     myQueue.dequeueItem()

#     print("Peek QValue", myQueue.peekQueue())