title: Python: how to get the number of GPUs
body: <p>I'm using Keras with Tensorflow to replicate a DQN. Actually I'm using 2 GPUs, but I want to make my code executable in every machine, regardless the number of GPUs it has. So my question is: how can I get the number of GPUs present in my PC? I checked <a href="https://stackoverflow.com/questions/38559755/how-to-get-current-available-gpus-in-tensorflow">this</a> but it gets me a lot of info I don't need. Is there any other way to get the number of GPUs?</p>