# Advance model building, why Split returns a Tuple?\[Pedagogical question\]

**URL:** <https://discourse.julialang.org/t/advance-model-building-why-split-returns-a-tuple-pedagogical-question/62882>\
**Category:** General Usage\
**Tags:** question\
**Created:** [June 14, 2021, 11:53am UTC](https://discourse.julialang.org/t/advance-model-building-why-split-returns-a-tuple-pedagogical-question/62882 "2021-06-14T11:53:53Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![deveshjawla](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/deveshjawla/32/16048_2.png) [@deveshjawla](https://discourse.julialang.org/u/deveshjawla)\
**Post date:** [June 14, 2021, 11:53am UTC](https://discourse.julialang.org/t/advance-model-building-why-split-returns-a-tuple-pedagogical-question/62882/1 "2021-06-14T11:53:53Z")

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In the advanced model building @ [https://fluxml.ai/Flux.jl/stable/models/advanced/#Multiple-outputs:-a-custom-Split-layer](https://fluxml.ai/Flux.jl/stable/models/advanced/#Multiple-outputs:-a-custom-Split-layer)

Is there any reason why a tuple is used in the code? see below for the exact line.

```julia
(m::Split)(x::AbstractArray) = tuple(map(f -> f(x), m.paths))

```