“do” with functions with “return”

do {a <- (* 2); b <- (+ 10); return (a + b)} $ 7 → 31
((* 2) >>= (\a -> ((+ 10) >>= (\b -> return (a + b)))))
(\r -> (\a -> ((+ 10) >>= (\b -> return (a + b)))) ((* 2) r) r)
(\r -> (\a -> (\r -> (\b -> return (a + b)) ((+ 10) r) r)) ((* 2) r) r)
(\r -> (\a -> (\r -> (return (a + ((+ 10) r))) r)) ((* 2) r) r)
(\r -> (\a -> (\r -> (return (a + (r + 10))) r)) ((* 2) r) r)
(\r -> (\a -> (\r -> (return (a + (r + 10))) r)) (r * 2) r)
(\r -> ((\r -> (return ((r * 2) + (r + 10))) r)) r)
(\r -> (\r -> (return ((r * 2) + (r + 10))) r) r) 7
((\r -> (return ((r * 2) + (r + 10))) r) 7)
(((return ((7 * 2) + (7 + 10))) 7))
((return ((7 * 2) + (7 + 10))) 7)
((return ((7 * 2) + (17))) 7)
((return ((14) + (17))) 7)
((return (14 + 17)) 7)
((return (31)) 7)
((return 31) 7)
(return 31) 7
return 31 7
-- ?
31