tap { next }
tap { next (1), (2), (3) }
tap { next 1 }
tap { next 1, 2,
3 }
tap { next 1, 2, 3 }
tap { next [1, 2, 3] }
tap { next(
1
2
) }
tap { next
1 }
tap { next() }
tap { next(1) }