fact: Definition forloop (n_1 n_2 : nat) (b : nat -> M unit) : M unit := if n_2 < n_1 then Ret tt else iteri (n_2.+1 - n_1) (fun i (m : M unit) => m >> b (n_1 + i)) skip.
imports: ssrmatching mathcomp(all_ssreflect) monae_lib HB(structures) hierarchy