public AsyncTennisFixtureService(IFixtureRepository fixtureRepository,
   IAsyncTennisFixtureStrategy fixtureStrategy, 
   ISqlLinqStoredProceduresRepository linqStoredProcRepository, ISqlStoredProceduresRepository sqlStoredProcRepository)
   : base(fixtureRepository, linqStoredProcRepository, sqlStoredProcRepository)
 {
   if (fixtureStrategy == null) throw new ArgumentNullException("fixtureStrategy");
   this.fixtureStrategy = fixtureStrategy;
 }
 public AsyncTennisFixtureService(IFixtureRepository fixtureRepository,
                                  IAsyncTennisFixtureStrategy fixtureStrategy,
                                  ISqlLinqStoredProceduresRepository linqStoredProcRepository, ISqlStoredProceduresRepository sqlStoredProcRepository)
     : base(fixtureRepository, linqStoredProcRepository, sqlStoredProcRepository)
 {
     if (fixtureStrategy == null)
     {
         throw new ArgumentNullException("fixtureStrategy");
     }
     this.fixtureStrategy = fixtureStrategy;
 }