LETTERS = ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V',
		   'W', 'X', 'Y', 'Z']


def get_letter_at_index(idx: int, capital: bool = False):
	if idx < 0 or idx > 25:
		raise AttributeError

	return LETTERS[idx] if capital else LETTERS[idx].lower()


def get_index_of_letter(letter: str):
	if letter.upper() not in LETTERS:
		raise AttributeError

	return LETTERS.index(letter.upper())