{ι : Type u_2} →
  {X : Type u_5} →
    {Y : ι → Type u_6} →
      {f : (i : ι) → X → Y i} →
        {motive : Metric.PiNatEmbed X Y f → Sort u} →
          (t : Metric.PiNatEmbed X Y f) → ((ofPiNat : X) → motive { ofPiNat := ofPiNat }) → motive t