Write a function subsets that uses recursive backtracking to find every possible sub-list of a given list.
A sub-list of a list L contains 0 or more of L's elements.
Your function should accept a list of strings as its parameter and print every sub-list that could be created from elements of that list, one per line.
For example, suppose a variable called lst stores the following elements:
[Janet, Robert, Morgan, Char]
The call of subsets(lst) would produce output such as the following:
['Janet', 'Robert', 'Morgan', 'Char']
['Janet', 'Robert', 'Morgan']
['Janet', 'Robert', 'Char']
['Janet', 'Robert']
['Janet', 'Morgan', 'Char']
['Janet', 'Morgan']
['Janet', 'Char']
['Janet']
['Robert', 'Morgan', 'Char']
['Robert', 'Morgan']
['Robert', 'Char']
['Robert']
['Morgan', 'Char']
['Morgan']
['Char']
[]
The order in which you show the sub-lists does not matter, and the order of the elements of each sub-list also does not matter.
The key thing is that your function should produce the correct overall set of sub-lists as its output.
Notice that the empty list is considered one of these sub-lists.
You may assume that the list passed contains no duplicates.
Do not use any loops in solving this problem.
