code: def bowtiedb(fa, keepDB):
      
      btdir = '%s/bt2' % (os.getcwd())
      # make directory for
      if not os.path.exists(btdir):
          os.mkdir(btdir)
      btdb = '%s/%s' % (btdir, fa.rsplit('/', 1)[-1])
      if keepDB is True:
          if os.path.exists('%s.1.bt2' % (btdb)):
              return btdb
      p = subprocess.Popen('bowtie2-build -q %s %s' \
          % (fa, btdb), shell = True)
      p.communicate()
      return btdb
docs: make bowtie db