python get uncompressed size of a .gz file

get_uncompressed_size.py

    def get_uncompressed_size(self, file):
        fileobj = open(file, 'r')
        fileobj.seek(-8, 2)
        crc32 = gzip.read32(fileobj)
        isize = gzip.read32(fileobj)  # may exceed 2GB
        fileobj.close()
        return isize

import gzip

def get_uncompressed_size(FileName):
    with gzip.open(FileName, 'rb') as fd:
        fd.seek(0, 2)
        size = fd.tell()
    return size