How do I unzip a .gz file in google cloud storage bucket?

Question

I modified the code from this thread to unzip a .gz file, but I'm getting the following error:

How do I unzip a .zip file in google cloud storage?

AttributeError: 'GzipFile' object has no attribute 'namelist'

My code is as follows:

from google.cloud import storage
from gzip import GzipFile
import io

def gzipextract(bucketname, gzipfilename_with_path):
    storage_client = storage.Client()
    bucket = storage_client.get_bucket(bucketname)

    destination_blob_pathname = gzipfilename_with_path

    blob = bucket.blob(destination_blob_pathname)
    gzipbytes = io.BytesIO(blob.download_as_string())

    with GzipFile(fileobj = gzipbytes, mode = 'r') as mygzip:
        for contentfilename in mygzip.namelist():
            contentfile = mygzip.read(contentfilename)
            blob = bucket.blob(gzipfilename_with_path + "/" + contentfilename)
            blob.upload_from_string(contentfile)