code: def _whctrs(anchor):
      """
      Return width, height, x center, and y center for an anchor (window).
      """
  
      w = anchor[2] - anchor[0] + 1
      h = anchor[3] - anchor[1] + 1
      x_ctr = anchor[0] + 0.5 * (w - 1)
      y_ctr = anchor[1] + 0.5 * (h - 1)
      return w, h, x_ctr, y_ctr
  
imports: import numpy
label_desc: Use image node_id 2 for calling a global function with example usage: _whctrs(anchor) and returns: w,  h,  x_ctr,  y_ctr