∀ {R : Type u_1} [inst : LinearOrder R] [inst_1 : TopologicalSpace R] (f : StieltjesFunction R)
  [inst_2 : OrderTopology R] [inst_3 : CompactIccSpace R] [inst_4 : MeasurableSpace R] [inst_5 : BorelSpace R]
  [inst_6 : SecondCountableTopology R] [inst_7 : DenselyOrdered R] {l : ℝ},
  Filter.Tendsto (↑f) Filter.atBot (nhds l) →
    ∀ (x : R), f.measure (Set.Iio x) = ENNReal.ofReal (Function.leftLim (↑f) x - l)