text: from catalyst.callbacks.metric import MetricCallback
  from catalyst.metrics import mrr
  
  
  class MRRCallback(MetricCallback):
      """Calculates the AUC  per class for each loader.
  
      .. note::
          Currently, supports binary and multi-label cases.
      """
  
      def __init__(
          self,
          input_key: str = "targets",
          output_key: str = "logits",
          prefix: str = "mrr",
      ):
          """
          Args:
              input_key (str): input key to use for mrr calculation
                  specifies our ``y_true``
              output_key (str): output key to use for mrr calculation;
                  specifies our ``y_pred``
              prefix (str): name to display for mrr when printing
          """
          super().__init__(
              prefix=prefix,
              metric_fn=mrr,
              input_key=input_key,
              output_key=output_key,
          )
  
  
  __all__ = ["MRRCallback"]
  