Using the definition of a sub list from Exercise 133, write a function that returns a list containing every possible sub list of a list. For example, the sub lists of [1, 2, 3] are [], [1], [2], [3],...

Using the definition of a sub list from Exercise 133, write a function that returns a list containing every possible sub list of a list. For example, the sub lists of [1, 2, 3] are [], [1], [2], [3], [1, 2], [2, 3] and [1, 2, 3]. Note that your function will always return a list containing at least the empty list because the empty list is a sub list of every list. Include a main program that demonstrate your function by displaying all of the sub lists of several different lists.