∀ {α : Type u_1} [inst : PseudoMetricSpace α] [inst_1 : MeasurableSpace α] [OpensMeasurableSpace α]
  (μ : MeasureTheory.Measure α) (C : NNReal) (x : α),
  ∀
    x_1 ∈
      {a |
        IsClosed a ∧
          (interior a).Nonempty ∧ ∃ r, a ⊆ Metric.closedBall x r ∧ μ (Metric.closedBall x (3 * r)) ≤ ↑C * μ a},
    MeasurableSet x_1