I was trying to follow this post to import the mopub SDK into my app, however Android Studio is being difficult.
I unzipped the SDK, and went to Project Structure
It's not fault of AndroidStudio, just try archived sdk, it works
https://github.com/mopub/mopub-android-sdk/archive/v3.9.0.zip
from https://github.com/mopub/mopub-android-sdk/releases
// sorry I don't enough reputation to post image