AWS: Lambda with Comprehend for Batch processing

lambda_function.py

import boto3

def datachunk(para):
    text_list = []
    while para:
        text_list.append(str(para[:4700]))
        para = para[4700:]
    return text_list[:25]

def lambda_handler(event, context):
    s3 = boto3.client("s3")
    bucket = "bucket-name"
    key = "filename.txt"
    file = s3.get_object(Bucket = bucket, Key = key)
    paragraph = str(file["Body"].read().decode("utf-8"))
    
    comprehend = boto3.client("comprehend")
    response = comprehend.batch_detect_key_phrases(TextList = datachunk(paragraph), LanguageCode = "en")
    for i in response["ResultList"]:
        for j in i["KeyPhrases"] :
            print(j["Text"])
    return 'Thanks for using'