code: def is_autosomal(chrom):
      
      try:
          int(chrom)
          return True
      except ValueError:
          try:
              int(str(chrom.lower().replace("chr", "").replace("_", "").replace("-", "")))
              return True
          except ValueError:
              return False
docs: Keep chromosomes that are a digit 1-22, or chr prefixed digit chr1-chr22