-- 1. 
filterDbDate :: [DatabaseItem] -> [UTCTime]
filterDbDate = foldr f []
  where f (DbDate x) xs = x : xs
        f _ xs = xs

-- 2.
filterDbDate :: [DatabaseItem] -> [UTCTime]
filterDbDate = foldr f []
  where f (DbDate x) xs = x : xs
        f _ xs = xs

-- 2.
filterDbDate = foldr f []
  where f (DbDate x) xs = x : xs
        f _ xs = xs

-- 2.