class_docstr: A five-way dictionary between Airflow task ids, Airflow cmds, ECS ARNs, and ECS task objects.
docstr: Get a task by AWS ARN.
docstr_tok: ["Get","a","task","by","AWS","ARN","."]
code: def task_by_arn(self, arn) -> EcsExecutorTask:
      """Get a task by AWS ARN."""
      return self.tasks[arn]
  
imports: from __future__ import annotations
  from collections import defaultdict
  from dataclasses import dataclass
  from typing import TYPE_CHECKING, Any, Callable, Dict, List
  from inflection import camelize
  from airflow.utils.state import State
label_desc: Use image node_id 5 for calling the EcsTaskCollection obj's underlying member method code with example usage: obj.task_by_arn(arn) and returns: self