Reveres singly-linked list in Python 3

reversed_linked_list.py

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next

def get_reversed_linked_list(self, root):
      current_node = root
      next_node = root.next
      pre_node = None

      while next_node is not None:
          current_node.next = pre_node

          pre_node = current_node
          current_node = next_node
          next_node = current_node.next

      current_node.next = pre_node

      return current_node