public PackageSource GetPackageSourceFor(DeployUnit deployUnit) { var matchingPackageSources = PackageSources.Where(x => x.Name == deployUnit.PackageInfo.Source).ToList(); if (matchingPackageSources.Count == 0) { throw new ConfigurationErrorsException($"The package source {deployUnit.PackageInfo.Source}, used by the deploy unit {deployUnit.Name}, does not exist"); } if (matchingPackageSources.Count > 1) { throw new ConfigurationErrorsException($"The package source {deployUnit.PackageInfo.Source}, used by the deploy unit {deployUnit.Name}, is declared more than once."); } return(matchingPackageSources.Single()); }