<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_link(self, task_id):
 """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. """

        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]