code: def parse_labels(labels_str):
      
      if not _LABELS_RE.match(labels_str):
          return None
      labels = {}
      for kv in _KV_RE.finditer(labels_str):
          gd = kv.groupdict()
          key = unquote(gd['key'])
          if key in labels:
              logger.warning('Duplicate label key "%s"', key)
          labels[key] = unquote(gd['val'])
      return labels
docs: Parse label keys and values following the Resource spec.
  
      >>> parse_labels("k=v")
      {'k': 'v'}
      >>> parse_labels("k1=v1, k2=v2")
      {'k1': 'v1', 'k2': 'v2'}
      >>> parse_labels("k1='v1,=z1'")
      {'k1': 'v1,=z1'}