code: def _create_merge_filelist(bam_files, base_file, config):
      
      bam_file_list = "%s.list" % os.path.splitext(base_file)[0]
      samtools = config_utils.get_program("samtools", config)
      with open(bam_file_list, "w") as out_handle:
          for f in sorted(bam_files):
              do.run('{} quickcheck -v {}'.format(samtools, f),
                     "Ensure integrity of input merge BAM files")
              out_handle.write("%s\n" % f)
      return bam_file_list
docs: Create list of input files for merge, ensuring all files are valid.