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Solve the following problem using Python, implementing the functions described below, one line at a time
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<USER_TASK:>
Description:
 def add_task(self, content, date=None, priority=None):
 """Add a task to the project :param content: The task description. :type content: str :param date: The task deadline. :type date: str :param priority: The priority of the task. :type priority: int :return: The added task. :rtype: :class:`pytodoist.todoist.Task` .. note:: See `here <https://todoist.com/Help/timeInsert>`_ for possible date strings. Install PyTodoist """

        response = API.add_item(self.owner.token, content, project_id=self.id,
                                date_string=date, priority=priority)
        _fail_if_contains_errors(response)
        task_json = response.json()
        return Task(task_json, self)