can anyone help me i have problem with this message below

namespace EmployeeService.Controllers { public class EmployeeController : ApiController { public IEnumerable Get() { using (Test_DBEntities test = new Test_DBEntities()) { return test.Customers.tolist(); } } } } ('EmployeeDataAccess.Test_DBEntities': type used in a using statement must be implicitly convertible to 'System.IDisposable')