docs: def get_short_reads(vals):
     (args,txome,seed,chunk) = vals
     #fast forward some ammount
     """Emit the short reads first"""
     txe = TranscriptomeEmitter(txome,TranscriptomeEmitter.Options(seed=seed))
     if args.weights:
        weights = {}
        if args.weights[-3:]=='.gz': inf = gzip.open(args.weights)
        else: inf = open(args.weights)
        for line in inf:
           f = line.rstrip().split("\t")
           weights[f[0]] = float(f[1])
        txs = {}
        for tx in txome.transcripts: txs[tx.name] = tx.length
        for name in weights:
           weights[name] *= txs[name]
        txe.set_weights_by_dict(weights)
     else:
        weights = {}
        txs = {}
        for tx in txome.transcripts: txs[tx.name] = tx.length
        txe.set_weights_by_dict(weights)
     reademit = ReadEmitter(txe)
     shortreads = []
     sp = args.short_read_insert_size
     reademit.cutter.set_custom(sp[0],sp[1],sp[2])
     if args.short_read_error_rate: 
        emfr = ErrorMakerFlatRate(rate=args.short_read_error_rate,rand=reademit.options.rand)
        reademit.add_error_maker(emfr)
     for i in range(0,chunk):
        e = reademit.emit(args.short_read_length)
        shortreads.append(e)
     return shortreads