title: Difference between `data` and `files` in Python requests
body: <p>My current understanding is that <code>data</code> and <code>files</code> both put data into the body of a POST (<code>requests.post()</code>) but what is the difference between them? When should one be used over the other, or both? And finally, could an HTTP API require that things be in one or the other, or can it not possibly matter because they are indistinguishable on the receiving end or something?</p>