b.py

#!/usr/bin/env python

from __future__ import print_function

from dark.diamond.alignments import DiamondReadsAlignments
from dark.fasta import FastaReads

reads = FastaReads('reads.fasta')
readsAlignments = DiamondReadsAlignments(reads, ['out.json.bz2'])

for readAlignments in readsAlignments:
    for alignment in readAlignments:
        if alignment.subjectTitle.find('arvovirus') > -1:
            print(readAlignments.read.toString('fasta'), end='')