class_docstr: Assign object detection proposals to ground-truth targets. Produces proposal
  classification labels and bounding-box regression targets.
code: def set_param_str(self, param_str):
      self.param_str_ = param_str
  
file_path: CNTK/Examples/Image/Detection/utils/caffe_layers/proposal_target_layer.py
imports: import yaml
  import numpy
  import numpy.random
  from utils.caffe_layers.default_config import cfg
  from utils.rpn.bbox_transform import bbox_transform
  from utils.cython_modules.cython_bbox import bbox_overlaps
label_desc: Use image node_id 1 for calling the ProposalTargetLayer obj's underlying member method code with example usage: obj.set_param_str(param_str) without return types