20 template<>
struct is_entity<Entity::Vertex> : std::true_type {};
21 template<>
struct is_entity<Entity::Edge> : std::true_type {};
22 template<>
struct is_entity<Entity::HalfEdge> : std::true_type {};
23 template<>
struct is_entity<Entity::Face> : std::true_type {};
24 template<>
struct is_entity<Entity::HalfFace> : std::true_type {};
25 template<>
struct is_entity<Entity::Cell> : std::true_type {};