let transform_fastq_reads       ?name ?fragment_id       (fq_reads: fastq_reads) r1 r2_opt     : fastq_reads     =      fastq_reads        ~host:fq_reads#r1#host       ~name:(match name with Some n -> n | None -> fq_reads#sample_name)       ?fragment_id:(         match fragment_id with         | Some fi -> fi         | None -> fq_reads#fragment_id)       r1 r2_opt