code: def _box_intersection(a, b):
      w = _overlap(a.x, a.w, b.x, b.w)
      h = _overlap(a.y, a.h, b.y, b.h)
      if w < 0 or h < 0:
          return 0
      return w * h
  
imports: from __future__ import division
  import math
  from collections import namedtuple
  from functools import cmp_to_key
  import numpy
label_desc: Use image node_id 4 for calling a global function with example usage: _box_intersection(a, b) and returns: unknown, int