code: def infer(self, main_program=None):
      if main_program is None:
          test_program = fluid.default_main_program().clone(
              for_test=True
          )
      else:
          test_program = main_program.clone(for_test=True)
      with fluid.program_guard(test_program):
          face_nmsed_out = fluid.layers.detection_output(
              self.face_mbox_loc,
              self.face_mbox_conf,
              self.prior_boxes,
              self.box_vars,
              nms_threshold=0.3,
              nms_top_k=5000,
              keep_top_k=750,
              score_threshold=0.01,
          )
      return test_program, face_nmsed_out
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import numpy
  import six
  import paddle.fluid
  from paddle.fluid.param_attr import ParamAttr
  from paddle.fluid.initializer import Xavier
  from paddle.fluid.initializer import Constant
  from paddle.fluid.initializer import Bilinear
  from paddle.fluid.regularizer import L2Decay
label_desc: Use image node_id 12 for calling the PyramidBox obj's underlying member method code with example usage: obj.infer(main_program) and returns: test_program,  face_nmsed_out