fact: Definition multispan_vertex {X : UU} (x : X) : vertex (multispan_graph X) := (inl x).
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Limits.Graphs.Colimits UniMath.Combinatorics.StandardFiniteSets UniMath.Combinatorics.FiniteSets