' islower(false 'isupper(false 'islower(false encrypting or decrypting each letter if symbol isupper()if num ord(' ')num - elif num ord(' ')num + line checks if the symbol is an uppercase letter if sothere are two special cases to worry about what if symbol was 'zand key was if that were the casethe value of num here would be the character '^(the ordinal of '^is but isn' letter at all you want the ciphertext to "wrap aroundto the beginning of the alphabet check if num has value larger than the ordinal value for "zif sothen subtract (because there are letters in totalfrom num after doing thisthe value of num is is the correct ordinal value for ' elif symbol islower()if num ord(' ')num - elif num ord(' ')num + if the symbol is lowercase letterthe program runs code that is similar to lines through the only difference is that it uses ord(' 'and ord(' 'instead of ord(' 'and ord(' 'in decrypting modethen key would be negative the special case would be where num - is less than the ascii value for "ain that caseadd to num to have it "wrap aroundto the end of the alphabet translated +chr(numelsetranslated +symbol line concatenates the encrypted/decrypted character to the translated string