def sort(fn):
    txt = get_txt(fn)
    word_list = []
    symbols = "!@#-$%^&*()\"_<>?,.[]{}`~'"

    for word in txt.split():
        clear_word = ""
        if word.isalpha():
            clear_word += word.lower()
        if clear_word not in symbols:
            word_list.append(clear_word)

    return word_list