# Cannot subtype of Distribution

**URL:** <https://discourse.julialang.org/t/cannot-subtype-of-distribution/38954>\
**Category:** General Usage\
**Created:** [May 7, 2020, 1:47pm UTC](https://discourse.julialang.org/t/cannot-subtype-of-distribution/38954 "2020-05-07T13:47:46Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![HenriDeh](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/henrideh/32/8316_2.png) [@HenriDeh](https://discourse.julialang.org/u/HenriDeh)\
**Post date:** [May 7, 2020, 1:47pm UTC](https://discourse.julialang.org/t/cannot-subtype-of-distribution/38954/1 "2020-05-07T13:47:47Z")

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I don’t get why I cannot create custom `Distribution` subtypes:

```julia
using Distributions
julia> struct Foo <: ContinuousUnivariateDistribution
       end

julia> Foo isa Distribution
false

julia> Foo isa ContinuousUnivariateDistribution
false

julia> struct Bar <: Distribution{Univariate,Continuous}
       end

julia> Bar isa Distribution
false

julia> struct Car <: Distributions.Distribution{Univariate,Continuous}
       end

julia> Car isa Distribution
false

```

Is there a problem with my subtyping ?

---

<div class="post-metadata">

**Author:** ![findmyway](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/findmyway/32/4946_2.png) [@findmyway](https://discourse.julialang.org/u/findmyway)\
**Post date:** [May 7, 2020, 2:03pm UTC](https://discourse.julialang.org/t/cannot-subtype-of-distribution/38954/2 "2020-05-07T14:03:57Z")

</div>

```julia
julia> Foo() isa Distribution
true

julia> Foo <: Distribution
true

```

---

<div class="post-metadata">

**Author:** ![HenriDeh](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/henrideh/32/8316_2.png) [@HenriDeh](https://discourse.julialang.org/u/HenriDeh)\
**Post date:** [May 7, 2020, 2:05pm UTC](https://discourse.julialang.org/t/cannot-subtype-of-distribution/38954/3 "2020-05-07T14:05:27Z")

</div>

I need sleep. Thank you