infix fun <T> OngoingStubbing<T>.doReturn(t: T): OngoingStubbing<T>
fun <T> OngoingStubbing<T>.doReturn(t: T, vararg ts: T): OngoingStubbing<T>
inline infix fun <reified T> OngoingStubbing<T>.doReturn(ts: List<T>): OngoingStubbing<T>