- , property $ \ut → Just (untag ut) ≡ fromAttempt (ca (retagHTTP (cs (ut2zt (untag (ut ∷ Tagged Cent20 UTCTime)))
- ∷ Tagged RFC822 Ascii)))
+ , property $ \ut → let zt = ut2zt $ untag (ut ∷ Tagged Cent20 UTCTime)
+ ut' = do a ← ca zt
+ ca $ retagHTTP (a ∷ Tagged RFC822 Ascii)
+ in
+ fromAttempt ut' ≡ Just (untag ut)