code: def _check_umi_type(bam_file):
      
      with pysam.Samfile(bam_file, "rb") as in_bam:
          for read in in_bam:
              cur_umi = None
              for tag in ["RX", "XC"]:
                  try:
                      cur_umi = read.get_tag(tag)
                      break
                  except KeyError:
                      pass
              if cur_umi:
                  if "-" in cur_umi and len(cur_umi.split("-")) == 2:
                      return "paired", tag
                  else:
                      return "adjacency", tag
docs: Determine the type of UMI from BAM tags: standard or paired.