     }
 
     public enum Errors: Error  {
+        case unsupportedType(String)
         case invalidNumberOfCoordinates(String)
     }
 

private let COORDINATES = "coordinates"
private let GEOMETRIES = "geometries"

public enum GeoJSONWriterError: Error {
    case unsupportedType(String)
}

///
/// GeoJSONWriter writer for GeoFeatures based on the Internet Engineering Task Force (IETF) proposed standard "The GeoJSON Format"
///

            return try self.geometryCollectionObject(geometryCollection)

        default:
            throw GeoJSONWriter.Errors.unsupportedType("Unsupported type \"\(String(describing: geometry.self))\".")
        }
    }

