code: def find_link(self, target_node):
          
          try:
              return next(l for l in self.link_list if l.target == target_node)
          except StopIteration:
              return None
docs: Find the link that points to ``target_node`` if it exists.
  
          If no link in ``self`` points to ``target_node``, return None
  
          Args:
              target_node (Node): The node to look for in ``self.link_list``
  
          Returns:
              Link: An existing link pointing to ``target_node`` if found
  
              None: If no such link exists
  
          Example:
              >>> node_1 = Node('One')
              >>> node_2 = Node('Two')
              >>> node_1.add_link(node_2, 1)
              >>> link_1 = node_1.link_list[0]
              >>> found_link = node_1.find_link(node_2)
              >>> found_link == link_1
              True