input: Write a function to create a linked list in python nodes. The function should return the head of the created linked list.
  
  def create_linked_list(data_list):
      if not data_list:
          return None
      head = ListNode(data_list[0])
      current = head
      for data in data_list[1:]:
          current.next = ListNode(data)
          current = current.next
      return head
  
  assert create_linked_list([1, 2, 3]).data == 1
  assert create_linked_list([1, 2, 3]).next.data == 2
  assert create_linked_list([1, 2, 3]).next.next.data == 3
  assert create_linked_list([1, 2, 3]).next.next.next == None
  assert create_linked_list([]).data == None
output: def create_linked_list(data_list):
      if not data_list:
          return None
      head = ListNode(data_list[0])
      current = head
      for data in data_list[1:]:
          current.next = ListNode(data)
          current = current.next
      return head