build :: [LogMessage] -> MessageTree
{--point full style
build [] = Leaf
build (msg : xsmsg) = insert msg (build xsmsg)
--}
{--haskell is very easy to abstract a function, foint free style : doesn't care about the data--}
build = foldr insert Leaf
build :: [LogMessage] -> MessageTree
build = foldr insert Leaf
build = foldr insert Leaf