class_docstr: Reader that reads from an upstream reader, calls the processor, and returns
  the processed record.
class_docstr_tok: ["Reader","that","reads","from","an","upstream","reader",",","calls","the","processor",",","and","returns","the","processed","record","."]
code: def setup_ex(self, init_net, finish_net):
      self.reader.setup_ex(init_net, finish_net)
  
imports: from caffe2.python import core, queue_util
  from caffe2.python.dataio import Reader, Writer
  from caffe2.python.net_builder import NetBuilder, ops
  from caffe2.python.schema import as_record, Field
  from caffe2.python.task import Node, Task, TaskGroup
label_desc: Use image node_id 3 for calling the ProcessingReader obj's underlying member method code with example usage: obj.setup_ex(init_net, finish_net) without return types