The following problem needs to be done in SML

All exercises should all have one-line solutions using map, foldr, or foldl. You can also use other predefined functions, of course, but do not write any additional named functions and do not use explicit recursion. . If you need helper functions, use anonymous ones. For example, if the problem says write a function add2 that takes an int list and returns the same list with 2 added to every element, your answer should be fun add2 x = map (fn a => a + 2) x;

Write a function lconcat of type 'a list list -> 'a list that takes a list of lists as input and returns the list formed by appending the input lists together in order. For example, if the input is [[1,2],[3,4,5,6],[7]], your function should return [1,2,3,4,5,6,7]. (There is a predefined function like this called concat, which of course you should not use.)