Memcache in Google Engine

I have an application developed in python and the Google engine, but when I try to configure this application, it gives me a time error compilation in the previous code, which works fine in real time. The code:

if version in ['beta', 'alpha'] :
            type=version
            version = memcache.get(type)
            if not version:
                v = RouterVersions.get_by_key_name(type)
                if not v : 
                    logging.error('No version found in RouterModel for %s', type)
                    self.error(404)
                    return;

                version = v.version
                memcache.add(v.type, version) 

when I use memcache.add or the get property, it gives a compile-time error of "undefined variable from import get". I can’t understand why this is so. I am new to python and google engine. My application was created in python 2.5, and now I'm using 2.7. Is this a problem or something else?