PYTHON: Use Python sets to write a function named letter_set that takes one argument, a Python list of English words. Yo

[answerhappygod]

PYTHON: Use Python sets to write a function named letter_set
that takes one argument, a Python list of English words. Your
function should return a list of all letters that are NOT used by
any of the words. Use only uppercase characters. Write a main
function that adequately tests letter_set .
For example letter_set['NOW', 'IS', 'THE', 'TIME'] should return
the list ['A', 'B', 'C', 'D', 'F', 'G', 'J', 'K', 'L', 'P', 'Q',
'R', 'U', 'V',' X', 'Y', 'Z']