code: def num_proposals(self):
      if self._proposal_cfg is None:
          return next(iter(self._proposal_dict.values())).shape[0]
      else:
          return self._proposal_cfg["NUM_ROI_PROPOSALS"]
  
imports: import os, sys
  import numpy
  import cv2
  from utils.rpn.bbox_transform import bbox_transform
  from utils.cython_modules.cython_bbox import bbox_overlaps
label_desc: Use image node_id 6 for calling the ProposalProvider obj's underlying member method code with example usage: obj.num_proposals() and returns: next, self