src/main/java/com/conveyal/gtfs/error/NewGTFSError.java
public static NewGTFSError forEntity(Entity entity, NewGTFSErrorType errorType) {
        NewGTFSError error = new NewGTFSError(entity.getClass(), errorType);
        error.lineNumber = entity.id;
        error.entityId = entity.getId();
        error.entitySequenceNumber = entity.getSequenceNumber();
        return error;
    }
public static NewGTFSError forEntity(Entity entity, NewGTFSErrorType errorType) {
        NewGTFSError error = new NewGTFSError(entity.getClass(), errorType);
        error.lineNumber = entity.id;
        error.entityId = entity.getId();
        error.entitySequenceNumber = entity.getSequenceNumber();
        return error;
    }
Factory Builder for cases where the entity has already been decoded and an error is discovered during validation