diff --git a/src/pathdecomposition/pathdecomposition.jl b/src/pathdecomposition/pathdecomposition.jl
index cc93781..3109229 100644
--- a/src/pathdecomposition/pathdecomposition.jl
+++ b/src/pathdecomposition/pathdecomposition.jl
@@ -9,7 +9,7 @@ struct Layout{T}
     neighbors::Vector{T}
     disconnected::Vector{T}
 end
-Base.hash(layout::Layout) = hash(layout.vertices)
+Base.hash(layout::Layout, h::UInt) = hash(layout.vertices, h)
 function Base.:(==)(l::Layout, m::Layout)
     l.vsep == m.vsep && l.vertices == m.vertices
 end