Error: invalid args

[LovingSalamander]

When I follow the README instructions for na-winit-glutin I get the following output:

$ cargo apk run
Using package `na-winit-glutin` in `/home/lovingsalamander/development/rust/rust-android-examples/na-winit-glutin/Cargo.toml`
Warning: Environment variable ANDROID_SDK_ROOT is deprecated (https://developer.android.com/studio/command-line/variables#envar). It will be used until it is unset and replaced by ANDROID_HOME.
Warning: Environment variable ANDROID_SDK_HOME is deprecated (https://developer.android.com/studio/command-line/variables#envar). It will be used until it is unset and replaced by ANDROID_USER_HOME.
Error: Invalid args.

I'm very unfamiliar with rust and I'm not sure where "Invalid args" is coming from or how to troubleshoot it.