getString won't resolve for me

[jkurtw]

On the step 8. SplitInstallManager listener the following code is added:
private val moduleKotlin by lazy { getString(R.string.module_feature_kotlin) }
private val moduleJava by lazy { getString(R.string.module_feature_java) }
private val moduleNative by lazy { getString(R.string.module_native) }
private val moduleAssets by lazy { getString(R.string.module_assets) }

However, getString is not happy for me. I tried a few different automatic fixes via option+enter, but none worked. I ended up just replacing this code with strings:
private val moduleKotlin = "module_feature_kotlin"
private val moduleJava = "module_feature_java"
private val moduleNative = "module_native"
private val moduleAssets = "module_assets"

I looked at the imports in the solution and don't see what I'm missing.