Using jython in JES, how can I achieve the following algorithm?

Assign the following character set to a variable (lets call it alphabet). Note the first five characters

are a period, comma, exclamation mark, question mark, and a space, followed by the 26 letters of

the alphabet. .,!? ABCDEFGHIJKLMNOPQRSTUVWXYZ

Create a loop setting a variable (shift) to a value of 0 through 30 (once for each character in the

character set).