public virtual object format(string format)
{
if (format == null)
{
//PhpException.ArgumentNull("format");
//return false;
throw new ArgumentNullException();
}
string fm = format.ToString();
if (string.IsNullOrEmpty(fm))
{
return false;
}
return DateTimeFunctions.FormatDate(fm, this.Time, this.TimeZone);
}