era.py
def is_date_type(cls):
    """Return True if the class is a date type."""
    if not isinstance(cls, type):
        return False
    return issubclass(cls, date) and not issubclass(cls, datetime)
def is_date_type(cls):
    """Return True if the class is a date type."""
    if not isinstance(cls, type):
        return False
    return issubclass(cls, date) and not issubclass(cls, datetime)
Return True if the class is a date type.