code: def _parse_perfdata(self, s):
          
          metrics = []
          counters = re.findall(self.TOKENIZER_RE, s)
          if counters is None:
              self.log.warning("Failed to parse performance data: {s}".format(
                  s=s))
              return metrics
  
          for (key, value, uom, warn, crit, min, max) in counters:
              try:
                  norm_value = self._normalize_to_unit(float(value), uom)
                  metrics.append((key, norm_value))
              except ValueError:
                  self.log.warning(
                      "Couldn't convert value '{value}' to float".format(
                          value=value))
  
          return metrics
docs: Parse performance data from a perfdata string