SolutionExtensions.SuggestionHandler.GetMissingExtensions C# (CSharp) Method

        public IEnumerable<IExtensionModel> GetMissingExtensions(IEnumerable<IExtensionModel> suggestedExtensions)
        {
            List<IExtensionModel> models = new List<IExtensionModel>();
            var installedExtensions = ExtensionInstalledChecker.Instance.GetInstalledExtensions();

            foreach (var extension in suggestedExtensions)
            {
                var installed = installedExtensions.FirstOrDefault(ins => ins.Header.Identifier.Equals(extension.ProductId, StringComparison.OrdinalIgnoreCase));

                if (installed == null)
                    models.Add(extension);
            }

            return models;
        }