intro name'
case h
name : String
val₁ val₂ : ℕ
s : State
⊢ ∀ (x : String), State.update name val₁ (State.update name val₂ s) x = State.update name val₁ s x
case h
name : String
val₁ val₂ : ℕ
s : State
name' : String
⊢ State.update name val₁ (State.update name val₂ s) name' = State.update name val₁ s name'