Set: pp::colors
  Set: pp::unicode
  Assumed: a
  Assumed: n
  Assumed: H1
  Assumed: H2
  Proved: T
  Set: lean::pp::coercion
  Set: lean::pp::notation
  Set: lean::pp::implicit
Theorem T : @eq ℤ (Int::add (Int::add a (nat_to_int n)) a) (nat_to_int 10) :=
    @Subst ℤ a (nat_to_int n) (λ x : ℤ, Int::add (Int::add a x) a == nat_to_int 10) H1 H2