∀ {ε : Type u_3} [inst : TopologicalSpace ε] [inst_1 : ENormedAddMonoid ε] {f : ℝ → ε} {μ : MeasureTheory.Measure ℝ}
  [TopologicalSpace.PseudoMetrizableSpace ε] {a : ℕ → ℝ} {n : ℕ},
  (∀ k < n, IntervalIntegrable f μ (a k) (a (k + 1))) → IntervalIntegrable f μ (a 0) (a n)