private
fun ApiTypeUsage.toTypeArgumentString(): String =
    "${variance.toKotlinString()}$sourceName${typeArguments.toTypeArgumentsString(type)}${isNullable.toKotlinNullabilityString()}"


private
fun Variance.toKotlinString() =
    when (this) {
        Variance.INVARIANT -> ""
        Variance.COVARIANT -> "out "
        Variance.CONTRAVARIANT -> "in "
    }