human
Complete this python program:
def export_date_time(format):
assistant
#Here is the Python program you requested.

    """A wrapper around strftime. Also returns \\ if the input is None.
    Args:
    format: Format string for strftime.
    Returns:
    Single argument method which convers a datetime into a string using format.
    """
    def export_date_time_lambda(value):
        if (not value):
            return ''
        return datetime.datetime.strftime(value, format)
    return export_date_time_lambda