docs: def is_invalid_date(d):
      """Return boolean to indicate whether date is invalid, None if valid, False if not a date
  
      >>> import datetime
      >>> is_invalid_date(datetime.datetime(1970, 1, 1, 0, 0, 1))
      >>> is_invalid_date(datetime.datetime(1970, 1, 1))
      >>> is_invalid_date(datetime.datetime(1969, 12, 31, 23, 59, 59, 999999))
      True
      >>> is_invalid_date(datetime.date(2100, 1, 1))
      True
      >>> is_invalid_date(datetime.datetime(2099, 12, 31, 23, 59, 59))
      >>> [is_invalid_date(x) for x in (None, 0, 1.0, '2000-01-01')]
      [False, False, False, False]
      """
      if not isinstance(d, DATE_TYPES):
          return False
      if d.year < 1970 or d.year >= 2100:
          return True