def PushFront(self, data):
node = Node(data)
node._next = self._head
self._head = node
if not self._tail:
self._tail = self._head
self._count += 1
def AddAfter(self, nd, data):
node2 = Node(data)
if self.Find(nd):
node = self.Find(nd)
node2._next = node._next
node._next = node2
if self._tail == node:
self._tail = node2
self._count += 1
def PushBack(self, data):
"""insert an item to the list"""
node = Node(data)
node._next = None
if not self._tail:
self._tail = node
self._head = self._tail
else:
self._tail._next = node
self._tail = node
self._count += 1
