2.21 Write an expression involving a three-letter string s that evaluates to a string whose characters are the characters of s in reverse order. If s is 'top', the expression should evaluate to 'pot'. 2.22 Write an expression involving string s containing the last and first name of a person— separated by a blank space—that evaluates to the person’s initials. If the string contained my first and last name, the expression would evaluate to 'LP'. 2.23 The range of a list of numbers is the largest difference between any two numbers in the list. Write a Python expression that computes the range of a list of numbers lst. If the list lst is, say, [3, 7, -2, 12], the expression should evaluate to 14 (the difference between 12 and -2). 2.24 Write the relevant Python expression or statement, involving a list of numbers lst and using list operators and methods for these specifications: (a) An expression that evaluates to the index of the middle element of lst (b) An expression that evaluates to the middle element of lst (c) A statement that sorts the list lst in descending order (d) A statement that removes the first number of list lst and puts it at the end 2.25 Add a pair of parentheses to each expression so that it evaluates to True. (a) 0 == 1 == 2 (b) 2 + 3 == 4 + 5 == 7 (c) 1 < -1 == 3 > 4