code: def run_samtools(align_bams, items, ref_file, assoc_files, region=None,
                   out_file=None):
      
      return shared_variantcall(_call_variants_samtools, "samtools", align_bams, ref_file,
                                items, assoc_files, region, out_file)
docs: Detect SNPs and indels with samtools mpileup and bcftools.