code: def __init__(self, loss_idx=-1, weight_idx=-1, name="RPNL1Loss"):
      super(RPNL1LossMetric, self).__init__(name)
      self.pred, self.label = get_rpn_names()
      self.loss_idx = loss_idx
      self.weight_idx = weight_idx
      self.name = name
  
imports: from __future__ import print_function
  import sys
  import mxnet
  import numpy
  from rcnn.config import config
label_desc: Use image node_id 1 to create a new RPNL1LossMetric object from inherited base classes: mx.metric with example: obj = RPNL1LossMetric(loss_idx, weight_idx, name)