Using GZIP Module with Python

I'm trying to use the Python GZIP module to simply uncompress several .gz files in a directory. Note that I do not want to read the files, only uncompress them. After searching this site for a while, I have this code segment, but it does not work:

import gzip
import glob
import os
for file in glob.glob(PATH_TO_FILE + "/*.gz"):
    #print file
    if os.path.isdir(file) == False:
        shutil.copy(file, FILE_DIR)
        # uncompress the file
        inF = gzip.open(file, 'rb')
        s = inF.read()
        inF.close()

the .gz files are in the correct location, and I can print the full path + filename with the print command, but the GZIP module isn't getting executed properly. what am I missing?