private Bond createBond(bondType type)
 {
     Bond bond=null;
     if(type.Equals(bondType.corp)){bond=new Corp();}
     else if(type.Equals(bondType.gov)){bond=new Corp();}
     return bond;
 }
 public Bond buyBond(bondType type)
 {
     Bond bond = createBond(type);
     bond.processing();
     return bond;
 }