How to use ListMetadata api call in Apex Salesforce Using Meta data service

MetadataService.ListMetadataQuery  obj= new MetadataService.ListMetadataQuery();
obj.type_x='Profile';
Double asOfVersion=33.0;
List<MetadataService.ListMetadataQuery> queries= new list<MetadataService.ListMetadataQuery>();
queries.add(obj);
 MetadataService.MetadataPort service = createService();  
MetadataService.FileProperties[] fileproperties  =service.listMetadata(queries,asOfVersion);
 public static MetadataService.MetadataPort createService()
    {
        MetadataService.MetadataPort service1 = new MetadataService.MetadataPort();
        service1.SessionHeader = new MetadataService.SessionHeader_element();
        service1.SessionHeader.sessionId = UserInfo.getSessionId();
        return service1;    
    }

for (MetadataService.FileProperties property :fileproperties)
{
 
    system.debug('****property-->Full Name***'+property.fullName);
   
   
}