∀ {E : Type u_2} {mE : MeasurableSpace E} {μ : MeasureTheory.Measure E} [inst : SeminormedAddCommGroup E]
  [inst_1 : InnerProductSpace ℝ E] [OpensMeasurableSpace E] [SecondCountableTopology E] [MeasureTheory.SFinite μ],
  Measurable (MeasureTheory.charFun μ)