code: def add_db_germline_flag(line):
      
      if line.startswith("#CHROM"):
          headers = ['##INFO=<ID=DB,Number=0,Type=Flag,Description="Likely germline variant">']
          return "\n".join(headers) + "\n" + line
      elif line.startswith("#"):
          return line
      else:
          parts = line.split("\t")
          if parts[7].find("STATUS=Germline") >= 0:
              parts[7] += ";DB"
          return "\t".join(parts)
docs: Adds a DB flag for Germline filters, allowing downstream compatibility with PureCN.