input: Write a python function to generate a linked list of n elements.
  assert generateLinkedList(5).next.data == 1
  assert generateLinkedList(3).next.next.data == 2
  assert generateLinkedList(0).data == 0
output: def generateLinkedList(n):
      class Node:
          def __init__(self, data):
              self.data = data
              self.next = None
  
      if n == 0:
          return Node(0)
      
      head = Node(0)
      current = head
      for i in range(1, n):
          current.next = Node(i)
          current = current.next
      
      return head