mapM_ :: Monad m => (a -> m b) -> [a] -> m ()
base Prelude, base Control.Monad
mapM_ f is equivalent to sequence_ . map f.
mapM_ :: (Foldable t, Monad m) => (a -> m b) -> t a -> m ()
base Data.Foldable
Map each element of a structure to a monadic action, evaluate these actions from left to right, and ignore the results.