public ServiceResult ChangeDrpParticipation(Guid stockId, bool participation)
{
if (_Portfolio == null)
{
return(ServiceResult <List <Holding> > .NotFound());
}
var holding = _Portfolio.Holdings[stockId];
if (holding == null)
{
return(ServiceResult.NotFound());
}
_Portfolio.ChangeDrpParticipation(stockId, participation);
return(ServiceResult.Ok());
}