code: def check(self, *exc_classes):
          
          for cls in exc_classes:
              cls_name = utils.cls_to_cls_name(cls)
              if cls_name in self._exc_type_names:
                  return cls
          return None
docs: Check if any of ``exc_classes`` caused the failure.
  
          Arguments of this method can be exception types or type
          names (strings **fully qualified**). If captured exception is
          an instance of exception of given type, the corresponding argument
          is returned, otherwise ``None`` is returned.