public Opportunity SaveOpportunity(Opportunity Opportunity)
        {
            Opportunity op = Opportunities.FirstOrDefault(v => v.id == Opportunity.id);

            if (op != null)
            {
                op.Name   = Opportunity.Name;
                op.Center = Opportunity.Center;
                op.Date   = Opportunity.Date;
            }
            return(op);
        }
 public Opportunity CreateOpportunity(Opportunity Opportunity)
 {
     if (Opportunities.Count != 0)
     {
         Opportunity.id = Opportunities.Max(v => v.id) + 1;
     }
     else
     {
         Opportunity.id = 1;
     }
     Opportunities.Add(Opportunity);
     return(Opportunity);
 }