How do i combine wav files (created using recorder.js) in python?

I am building a client-server application using python and javascript. In the frontend, i'm recording audio using recorder.js. After some fixed interval, i use exportWav() and send the audio file to the server. At the backend i now need to concatenate these files to make the bigger audiofile again.

I saw this question, but i don't have actual .wav files, just the blobs returned by exportWav.

I'm also using app engine, so i cannot write output to a wav file. I need to create another audioblob that i can store in the datastore.

Any ideas?