Python-сообщество

 def the_most_wanted_letter(text: str) -> str:
    temp = {}
    for word in text.lower():
        if word.isalpha():
            temp.setdefault(word, 0)
            temp[word] += 1
    return sorted(temp.items(), key=lambda x: (-x[1], x[0]))[0][0]

 key=lambda x: [b](-x[1][/b], x[0])