first: ->
return 'do' for x in [1,2,3]
second: ->
return ['re' for x in [1,2,3]]
third: ->
return ('mi' for x in [1,2,3])
ok first().join(' ') is 'do do do'
ok second()[0].join(' ') is 're re re'
ok third().join(' ') is 'mi mi mi'