def is_negated(tok):
    """
    Checks if a token is negated.
    :param tok: the token to be checked.
    :return: True if the token is negated, False otherwise.
    """
    negations = {"no", "not", "n't", "never", "none"}
    for dep in list(tok.lefts) + list(tok.rights):
        if dep.lower_ in negations:
            return True
    return False