apply congrArg construct
C : _root_.Container
R S : Type u₁
r : R
k : R → Free C S
⊢ construct (Map (corec (bind.automaton k)) (bind.automaton k (Sum.inl (construct (Functor.Pure r))))) =
    construct (destruct (k r))
C : _root_.Container
R S : Type u₁
r : R
k : R → Free C S
⊢ Map (corec (bind.automaton k)) (bind.automaton k (Sum.inl (construct (Functor.Pure r)))) = destruct (k r)