code: def get_link(self, task_id):
          
          links = [x for x in self.links if x.task_id == task_id]
          if len(links) != 1:
              raise CoTError("No single Link matches task_id {}!\n{}".format(task_id, self.dependent_task_ids()))
          return links[0]
docs: Get a ``LinkOfTrust`` by task id.
  
          Args:
              task_id (str): the task id to find.
  
          Returns:
              LinkOfTrust: the link matching the task id.
  
          Raises:
              CoTError: if no ``LinkOfTrust`` matches.