Letter Function

A$-$B: is$\_$empty$\_$set$($S$)$

C$-$D: is$\_$element $(E,S)$

$E-F$ : is$\_$sub$\_$set$(A,B$

G$-$H: is$\_$equal$\_$set$(A,B)$

I$-$J$-$K: union$($A$,$ B$)$

L$-$M$-$N: intersection$($A$,$ B$)$

O$-$P$-$Q: difference$($A$,$ B$)$

R$-$S$-$T: symmetric$\_$difference$($A$,$ B$)$

U$-$V$-$W: Cartesian$\_$product$($A$,$ B$)$

$x-Y-Z$ : power$($S$)$

Definition$/$Explanation

true if set $S$ is empty set; false if set $S$ is not empty set true if $E$ is an element of $S$; false if $E$ is not an element of $S$ true if $A$ is a subset of $B$; false if $A$ is not a subset of $B$ true if $A$ is equal to $B$; false if $A$ is not equal to $B$ compute and return union of a set A and a set $B$ compute and return intersection of a set A and a set $B$ compute and return difference of a set A and a set $B$ compute and return symmetric difference of a set A and a set compute and return Cartesian product of a set A and a set $B$ compute and return power set of a set $S$

Write in Python:

the selected function

a program to:

input$/$read input data from the keyboard,

call and execute the selected function, and

output result$/$output data on the screen of terminal.

The function may print$/$report only errors.

The function should not print the computed value.

The function should return the computed value.

The function$($s$)$ and program must be into two separate python files.

The function$($s$)$ and program must be designed from scratch.

It is not allowed to use standard and library functions.