Please, write a python script to quickly synchronise a large list of files between S3 and local storage.
Here's an example Python program that uses the boto3 library to synchronize a large list of files between Amazon S3 (using the s3.client) and local storage (using the os module):

import boto3
from os import listdir, walk

# Set up credentials for S3
s3 = boto3.resource('s3')
bucket_name ='my-s3-bucket'
key = 'files.txt'

# List all files in S3
result = s3.list_objects(Bucket=bucket_name, Prefix='.', MaxKeys=1000)
for obj in result['Items']:
    filename = obj['Key'] + '.txt'
    fullpath = '/'.join([bucket_name, filename])

    if not os.path.exists(fullpath):
        os.makedirs(fullpath)

    with open(fullpath, 'w+') as file:
        file.write(obj['Body'])

# Walk through each directory in local storage
for dirpath, dirnames, filenames in walk(local_directory):
    for f in filenames:
        fullpath = dirpath + '/' + f
        if not os.path.exists(fullpath):
            os.makedirs(fullpath)

    for obj in dirnames:
        filename = obj + '.txt'
        fullpath = '/'.join([local_directory, filename])

        if not os.path.exists(fullpath):
            os.makedirs(fullpath)

        with open(fullpath, 'w+') as file:
            file.write(obj['Body'])