Trying to create a ContentType with a class in a package. Does anyone know how this should be done?

    using Umbraco.Cms.Core.Models; 
    using Umbraco.Cms.Core.Services; 

    namespace MyProject
    {
        public class ContentTypeCreator
        {
            private readonly IContentTypeService _contentTypeService;

        public ContentTypeCreator(IContentTypeService contentTypeService)
        {
            _contentTypeService = contentTypeService;
        }

        public void CreateContentType()
        {
            var ct = new ContentType(-1)
            {
                Alias = "MyContentType",
                Name = "My Content Type",
                Description = "This is my custom content type",
                Icon = "icon-document"
            };

            _contentTypeService.Save(ct);
        }
    }
}