We say a list is $$squished$$ if it is sorted, has no duplicate elements, and does not have any embedded lists. We squish a list L by first removing all sublists within L and replacing them with their members $($e$.$g$.[1,[2,3],4]$ would become $[1,2,3,4],$ second we remove all duplicate values in the resulting list, and finally we sort the result. Write a Prolog rule squish$/2$ which squishes a list $($without using any built$-$in functions or rules other than sort$/2).$ For example:

$?-$ squish$([1,2,[3,4,[5,6],7],8,9,[2,4,5,8]],[1,2,3,4,5,6,7,8,9]).$

true.

$?-$ squish$([$a$,$b$,$c$,[$d$,$e$],$f$,[$c$,$ a$,$ b$]],[$d$,$e$,$f$,$c$,$a$,$b$]).\%$ result not sorted

false.

$?-$ squish$([1,[2,3],[4,5,6],7,1,2,3],[1,[2,3],[4,5,6],7]).\%$ result has sublists

false.

$?-$ squish$([1,[2,4],[4,[5],6],[5,2,1],[9,4,5],[8,4,2],3],$X$).$

X $=[1,2,3,4,5,6,8,9]$