code: def remove_isoforms(ids):
      
      key = lambda x: x.rsplit(".", 1)[0]
      iso_number = lambda x: get_number(x.split(".")[-1])
      ids = sorted(ids, key=key)
      newids = []
      for k, ii in groupby(ids, key=key):
          min_i = min(list(ii), key=iso_number)
          newids.append(min_i)
      return newids
docs: This is more or less a hack to remove the GMAP multiple mappings. Multiple
      GMAP mappings can be seen given the names .mrna1, .mrna2, etc.