airflow/models/taskinstance.py
def key(self):
        """
        Returns a tuple that identifies the task instance uniquely
        """
        return self.dag_id, self.task_id, self.execution_date, self.try_number
def key(self):
        """
        Returns a tuple that identifies the task instance uniquely
        """
        return self.dag_id, self.task_id, self.execution_date, self.try_number
Returns a tuple that identifies the task instance uniquely