public override bool ChangePassword(string username, string oldPassword, string newPassword)
{
Condition.Requires(username, "username").IsNotNullOrWhiteSpace();
Condition.Requires(oldPassword, "oldPassword").IsNotNullOrWhiteSpace();
Assert(this.ValidatePassword(newPassword, username), MembershipCreateStatus.InvalidPassword);
return base.ChangePassword(username, oldPassword, newPassword);
}