@Kha, I was having to use `(run ...).1` in many places
in my code. So, I changed the instance
```
instance (σ m out) [monad_run out m] : monad_run (λ α, σ → out (α × σ)) (state_t σ m) :=
⟨λ α x, run ∘ (λ σ, x.run σ)⟩
```
to
```
instance (σ : Type u) (m out : Type u → Type v) [functor m] [monad_run out m] : monad_run (λ α, σ → out α) (state_t σ m) :=
⟨λ α x, run ∘ (λ σ, prod.fst <$> (x.run σ))⟩
```
If we want to get the resultant state in an action `act`, we can just
use `run (act >> get) init_state`.
874f9caf13