code: def check(self, *exc_classes):
          
          if not exc_classes:
              return None
          for cause in self:
              result = cause.check(*exc_classes)
              if result is not None:
                  return result
          return None
docs: Check if any of exception classes caused the failure/s.
  
          :param exc_classes: exception types/exception type names to
                              search for.
  
          If any of the contained failures were caused by an exception of a
          given type, the corresponding argument that matched is returned. If
          not then ``None`` is returned.