code: def get_labels(filename, logger=None):
      
      labeldict = {}
      if filename is not None:
          if logger:
              logger.info("Reading labels from %s", filename)
          with open(filename, "r") as ifh:
              count = 0
              for line in ifh.readlines():
                  count += 1
                  try:
                      key, label = line.strip().split("\t")
                  except ValueError:
                      if logger:
                          logger.warning("Problem with class file: %s", filename)
                          logger.warning("%d: %s", (count, line.strip()))
                          logger.warning("(skipping line)")
                      continue
                  else:
                      labeldict[key] = label
      return labeldict
docs: Returns a dictionary of alternative sequence labels, or None
  
      - filename - path to file containing tab-separated table of labels
  
      Input files should be formatted as <key>\t<label>, one pair per line.