Returns whether the path is a directory or not.

def isdir(self, dirname):
        """Returns whether the path is a directory or not."""
        client = boto3.client("s3")
        bucket, path = self.bucket_and_path(dirname)
        if not path.endswith("/"):
            path += "/"  # This will now only retrieve subdir content
        r = client.list_objects(Bucket=bucket, Prefix=path, Delimiter="/")
        if r.get("Contents") or r.get("CommonPrefixes"):
            return True
        return False