code: def check_configs(self):
      if self.config["num-filters"] == -1:
          raise RuntimeError(
              "You must specify num-filters for res2-block."
          )
  
imports: from __future__ import print_function
  from __future__ import division
  import math
  import re
  import sys
  from libs.nnet3.xconfig.basic_layers import XconfigLayerBase
label_desc: Use image node_id 4 for calling the XconfigRes2Block obj's underlying member method code with example usage: obj.check_configs() without return types