code: def samtools(items):
      
      samtools = config_utils.get_program("samtools", items[0]["config"])
      p = subprocess.Popen([samtools, "sort", "-h"], stdout=subprocess.PIPE,
                           stderr=subprocess.PIPE)
      output, stderr = p.communicate()
      p.stdout.close()
      p.stderr.close()
      if str(output).find("-@") == -1 and str(stderr).find("-@") == -1:
          return ("Installed version of samtools sort does not have support for "
                  "multithreading (-@ option) "
                  "required to support bwa piped alignment and BAM merging. "
                  "Please upgrade to the latest version "
                  "from http://samtools.sourceforge.net/")
docs: Ensure samtools has parallel processing required for piped analysis.