import string


def keep_candidate_token(candidate):
    """Filter out undesired candidate tokens."""
    # Filter out candidates with punctuation and numbers.
    remove_punc = str.maketrans("", "", string.punctuation)
    new_candidate = candidate.translate(remove_punc)
    remove_digits = str.maketrans("", "", string.digits)
    new_candidate = new_candidate.translate(remove_digits)
    # Filter out byte tokens.
    if new_candidate.isprintable():
        return candidate == new_candidate
    else:
        return False