Why does NextContinuationToken is the same in every s3 response?

I am processing significant amount of files (about 9000 files) via S3

I am using next_token = response.get("NextContinuationToken") to process parts of keys

I found a problem -- next_token value is always the same (name of object in my s3). Thus I have an infinite loop.

What is wrong with my code? Why do I have the same value of next_token variable

My code

import boto3import botocoreclass S3Manager:    def __init__(self, config) -> None:        # Set certs and secrets here         aws_config = boto3.session.Config (            signature_version='s3v4',            connect_timeout=100,            client_cert=ssl_certs        )        self.s3_client = boto3.client(storage_type,                 endpoint_url=self.endpoint,                aws_access_key_id=access_key,                aws_secret_access_key=secret_key,                aws_session_token=None,                config=aws_config,            )    def get_folders(self, bucket_name, prefix=""):        folders = []        default_kwargs = {"Bucket": bucket_name,"Prefix": prefix        }        next_token = ""        while next_token is not None:            updated_kwargs = default_kwargs.copy()            if next_token != "":                updated_kwargs["ContinuationToken"] = next_token            response = self.s3_client.list_objects_v2(**default_kwargs)            # Appending data to folders list                  next_token = response.get("NextContinuationToken")            self.logger.debug(f"DEBUG_ S3 next_token {next_token}") # see the same value every iteration        return folders