How would i change this: " try:
userChoice = input("Would you like to Add or Multipy?(A/M): ")
except:
print("Please enter 'A' or 'M'") "

so it only allows me to put "A" or "M" so that it runs the except part

*write a program that defines symbolic names for several string literals (chars between quotes). * use each symbolic name in a variable definition. * use of symbolic to compose the assembly code instruction set can perform vara = (vara - varb) + (varc - vard); ensure that variable is in unsigned integer data type. * you should also further enhance your symbolic logic block to to perform expression by introducing addition substitution rule. vara = (vara+varb) - (varc+vard).