def to_date(value, default=None):
    """Tries to convert the passed in value to Zope's DateTime

    :param value: The value to be converted to a valid DateTime
    :type value: str, DateTime or datetime
    :return: The DateTime representation of the value passed in or default
    """
    if isinstance(value, DateTime):
        return value
    if not value:
        if default is None:
            return None
        return to_date(default)
    try:
        if isinstance(value, str) and '.' in value:
            # https://docs.plone.org/develop/plone/misc/datetime.html#datetime-problems-and-pitfalls
            return DateTime(value, datefmt='international')
        return DateTime(value)
    except:
        return to_date(default)
Tries to convert the passed in value to Zope's DateTime

    :param value: The value to be converted to a valid DateTime
    :type value: str, DateTime or datetime
    :return: The DateTime representation of the value passed in or default