norm ExpA (BindE v _ (ReturnE e) m)                = do  insertSubst VarA v ExpA e
                                                         norm ExpA m
norm ExpA (BindE v _ (ReturnE e) m)                = do  insertSubst VarA v ExpA e
                                                         norm ExpA m
norm ExpA (BindE v _ (ReturnE e) m)                = do  insertSubst VarA v ExpA e
                                                         norm ExpA m