class_docstr: Implement a fbmessenger to parse incoming webhooks and send msgs.
docstr: Check if the users message is an image.
docstr_tok: ["Check","if","the","users","message","is","an","image","."]
code: def _is_image_message(message: Dict[Text, Any]) -> bool:
      """Check if the users message is an image."""
      return (
          "message" in message
          and "attachments" in message["message"]
          and message["message"]["attachments"][0]["type"] == "image"
      )
  
imports: import copy
  import hashlib
  import hmac
  import logging
  import structlog
  from fbmessenger import MessengerClient
  from fbmessenger.attachments import Image
  from fbmessenger.elements import Text
  from fbmessenger.quick_replies import QuickReplies, QuickReply
  from fbmessenger.sender_actions import SenderAction
  import rasa.shared.utils.io
  from sanic import Blueprint, response
  from sanic.request import Request
  from typing import Text, List, Dict, Any, Callable, Awaitable, Iterable, Optional, Union
  from rasa.core.channels.channel import UserMessage, OutputChannel, InputChannel
  from sanic.response import HTTPResponse
label_desc: Use image node_id 5 for calling the Messenger obj's underlying member method code with example usage: obj._is_image_message(message) and returns: unknown