fact: Definition kfinite_subtype_union {X I : UU} (index : I -> kfinite_subtype X) (index_finite : isfinite I) : kfinite_subtype X.
imports: UniMath.Foundations.Propositions UniMath.MoreFoundations.PartA UniMath.MoreFoundations.Notations UniMath.Combinatorics.FiniteSets UniMath.Combinatorics.StandardFiniteSets UniMath.MoreFoundations.Subtypes UniMath.Combinatorics.KFiniteTypes