python2.6でgzipのbuffer扱えないのでしょうがないからこんな感じでつかうらしい

python26_gzipstream.py

from gzip import GzipFile
from StringIO import StringIO

class GZOStream:
    def __init__(self):
        self.sio = StringIO()
        self.gzf = GzipFile(fileobj=self.sio, mode='wb')

    def write(self,data):
        self.gzf.write(data)

    def finish(self):
        self.gzf.close()
        buf = self.sio.getvalue()
        self.sio.close()
        return buf

class GZIStream:
    def __init__(self, buff):
        self.sio = StringIO(buff)
        self.gzf = GzipFile(fileobj=self.sio, mode='rb')

    def read(self):
        return self.gzf.read()

    def close(self):
        self.gzf.close()
        self.sio.close()

go = GZOStream()
go.write("aiiiiaaa")
gi = GZIStream(go.finish())
print gi.read()

python3ならこんな苦労はない