def is_year_range(text):
    """
    Return True if `text` is a year range.
    """
    if not text:
        return
    if all(c.isdigit() for c in text):
        return True

    digit_punct = set('''!"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~ 1234567890''')
    if all(c in digit_punct for c in text) and any(c.isdigit() for c in text):
        return True