Binboo.Jira.Commands.LabelCommand.ParseLabelOperation C# (CSharp) Method

        private static Action<IList<string>> ParseLabelOperation(string labelOperation)
        {
            switch(labelOperation[0])
            {
                case LabelOperations.Add: return labels =>
                                                 	{
                                                        var label = LabelFrom(labelOperation);
                                                        if (!labels.Contains(label, StringComparer.InvariantCultureIgnoreCase))
                                                        {
                                                            labels.Add(label);
                                                        }
                                                 	};

                case LabelOperations.Remove: return labels => labels.Remove(LabelFrom(labelOperation));
            }

            throw new ArgumentException("Invalid label operation for label: " + labelOperation, "labelOperations");
        }