Write a function called filter-seq that takes a sequence s (a string) and an alphabet a (a string), and generates a result sequence (a string) by including only the characters of s that occur in the alphabet a.

In another lisp file called test-cases.lisp, write the program below which includes a main function that calls a test case that your solution for this exercise must pass.

(deftest test-filter-seq ()  (check    (equal (filter-seq "sdafgacs" "abcf") "afac")    (equal (filter-seq "AaafFSs" "SFAa") "AaaFS")    (equal (filter-seq "abcdfG" "abg") "ab")    (equal (filter-seq "" "abcf")  "")    (equal (filter-seq "sdafgacs" "") "")    (equal (filter-seq "sdafgacs" "abcfs") "safacs"))) (defun main ()  (test-filter-seq))

To test your function filter-seq:

RTL-USER> (load "filter-seq.lisp") RTL-USER> (load "test-cases.lisp") RTL-USER> (main)

Make sure your filter-seq.lisp in the folder Exercise-1/ contails only your filter-seq function and other helper functions you yourself may have decided to write. Notice: it should not containg any calls to function load, i.e., it should not contain (load "filter-seq.lisp") and it should not contain (load "test-cases.lisp")

This is a lisp program problem: