Question 7: Write the standard ml code using pattern matching for the function "combine", which takes two lists and returns a single list containing all the elements from input lists without duplication. For example, combine [1,2,3,4][2,3,4,5,6] will return [1,2,3,4,5,6]. Once you create your function combine,sample input and write the expected output (result) with your pen and paper. Do not use a computer! Briefly explain your code to get credit