from typing import List
from typing import Optional


def _absent(word: str, a_chars: List) -> Optional[str]:
    """
    Checks a word for absence of characters from a User defined list.
    :param word: String containing the word to test against the list of absences.
    :param a_chars: List of characters absent in the word.
    :return: String containing the word if it doesn't contain the a_chars; None if it does.
    """
    matches: List = []

    for char in a_chars:
        if char not in word:
            matches.append(True)
        else:
            matches.append(False)

    if all(matches):
        return word

    return None