lambda_function.py

import  requests
import  json
import  os

HEADER = {
    'Content-type': 'application/json',
    'Authorization': 'Bearer ' + 'Channel Access Token'
}

def lambda_handler(event, context):

    body = json.loads(event['body'])

    for event in body['events']:

        payload = {
            'replyToken': event['replyToken'],
            'messages': []
        }

        if event['message']['type'] == 'text':
            payload['messages'].append({
                'type': 'text',
                'text': event['message']['text']
            })
        elif event['message']['type'] == 'sticker':
            payload['messages'].append({
                'type': 'sticker',
                'stickerId': event['message']['stickerId'],
                'packageId': event['message']['packageId']
            })

        if len(payload['messages']) > 0:
            response = requests.post('https://api.line.me/v2/bot/message/reply',
                headers=HEADER,
                data=json.dumps(payload))