code: def bbox_xyxy_to_cxcywh(x):
      x1, y1, x2, y2 = x.split(4, axis=-1)
      return paddle.concat(
          [(x1 + x2) / 2, (y1 + y2) / 2, (x2 - x1), (y2 - y1)], axis=-1
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import copy
  import math
  import paddle
  import paddle.nn
  import paddle.nn.functional
  from ..bbox_utils import bbox_overlaps
label_desc: Use image node_id 3 for calling a global function with example usage: bbox_xyxy_to_cxcywh(x) and returns: paddle