creating a lead in webservice

private Guid CreateLead(IOrganizationService _service)

{

Entity Lead = new Entity("lead");

Lead.Attributes["Topic"] = "************";

Lead.Attributes["FirstName"] = "*";

Lead.Attributes["LastName"] = "*****"

Lead.Attributes["CompanyName"] = "****"

Lead.Attributes["Email"] = "****"

Guid id = _service.Create(Lead);

Error message

'Leadaccount.CreateLead(Microsoft.Xrm.Sdk.IOrganizationService)': not all code paths return a value

Question about Outlook Express