code: def _init_itemid2name(self):
          
          if not hasattr(self.args, 'id2sym'):
              return None
          fin_id2sym = self.args.id2sym
          if fin_id2sym is not None and os.path.exists(fin_id2sym):
              id2sym = {}
              cmpl = re.compile(r'^\s*(\S+)[\s,;]+(\S+)')
              with open(fin_id2sym) as ifstrm:
                  for line in ifstrm:
                      mtch = cmpl.search(line)
                      if mtch:
                          id2sym[mtch.group(1)] = mtch.group(2)
              return id2sym
docs: Print gene symbols instead of gene IDs, if provided.