Convert string to date or datetime

convert string to datetime

    def __init__(self, format=None):
        if format is None:
            if not settings.DATETIME_INPUT_FORMATS:
                formats = ("%Y-%m-%d %H:%M:%S",)
            else:
                formats = settings.DATETIME_INPUT_FORMATS
        else:
            formats = (format,)
        self.formats = formats

    def clean(self, value, row=None, *args, **kwargs):
        if not value:
            return None
        if isinstance(value, datetime):
            return value
        for format in self.formats:
            try:
                dt = datetime.strptime(value, format)
                if settings.USE_TZ:
                    # make datetime timezone aware so we don't compare
                    # naive datetime to an aware one
                    dt = timezone.make_aware(dt,
                                             timezone.get_default_timezone())
                return dt
            except (ValueError, TypeError):
                continue
        raise ValueError("Enter a valid date/time.")