∀ {C : Type u_5} [inst : CategoryTheory.Category.{u_4, u_5} C] {D : Type u_3}
  [inst_1 : CategoryTheory.Category.{u_2, u_3} D] {K : CategoryTheory.GrothendieckTopology D}
  {G : CategoryTheory.Functor C D} {ℱ' : CategoryTheory.Sheaf K (Type u_1)} [G.IsCoverDense K] (X : D),
  CategoryTheory.Presieve.IsSheafFor ℱ'.val (CategoryTheory.Sieve.coverByImage G X).arrows