A Doubly Linked List implementation of a dual purposed Stack and Queue

Staq.py

class StaqNode:
  def __init__(self, val=None, left=None, right=None):
    self.val = val
    self.left = left
    self.right = right 

class Staq:
  def __init__(self):
    self.head = None 
    self.tail = None 
    self.size = 0

  def insert(self, val):
    # 0 nodes
    if not self.head and not self.tail:
      node = StaqNode(val=val)
      self.head = self.tail = node 
    # >= 1 node
    else:
      node = StaqNode(val=val)
      node.left = self.tail
      self.tail.right = node 
      self.tail = node 
    self.size += 1 
  
  def pop(self, head=True, val=False):
    if self.size == 0:
      return None
    
    elif self.size == 1:
      node = self.head
      if not node:
        node = self.tail
      self.tail = None 
      self.head = None 

    else:
      if head:
        node = self.head 
        self.head = node.right
        if self.head:
          self.head.left = None 
      
      else:
        node = self.tail
        self.tail = node.left 
        if self.tail:
          self.tail.right = None 

    self.size -= 1      
    if val:
      return node.val 
    return node 


  def printStaq(self):
    curr = self.head
    while curr: 
      print(curr.val) 
      curr = curr.right