code: def _match(cls, el, spec):
          "Return the strength of the match (None if no match)"
          spec_dict = dict(zip(['type', 'group', 'label'], spec.split('.')))
          if not isinstance(el, Image) or spec_dict['type'] != 'Image':
              raise NotImplementedError("Only Image currently supported")
  
          sanitizers = {'group':group_sanitizer, 'label':label_sanitizer}
          strength = 1
          for key in ['group', 'label']:
              attr_value = sanitizers[key](getattr(el, key))
              if key in spec_dict:
                  if spec_dict[key] != attr_value: return None
                  strength += 1
          return strengtf _match(cls, el, spec):
          "Return the strength of the match (None if no match)"
          spec_dict = dict(zip(['type', 'group', 'label'], spec.split('.')))
          if not isinstance(el, Image) or spec_dict['type'] != 'Image':
              raise NotImplementedError("Only Image currently supported")
  
          sanitizers = {'group':group_sanitizer, 'label':label_sanitizer}
          strength = 1
          for key in ['group', 'label']:
              attr_value = sanitizers[key](getattr(el, key))
              if key in spec_dict:
                  if spec_dict[key] != attr_value: return None
                  strength += 1
          return strength
docs: Return the strength of the match (None if no match)