code: def _generate_base_anchors(base_size, scales, aspect_ratios):
      """Generate anchor (reference) windows by enumerating aspect ratios X
      scales wrt a reference (0, 0, base_size - 1, base_size - 1) window.
      """
      anchor = (
          np.array([1, 1, base_size, base_size], dtype=np.float) - 1
      )
      anchors = _ratio_enum(anchor, aspect_ratios)
      anchors = np.vstack(
          [
              _scale_enum(anchors[i, :], scales)
              for i in range(anchors.shape[0])
          ]
      )
      return anchors
  
file_path: gluon-cv/gluoncv/model_zoo/rcnn/rpn/anchor.py
imports: from __future__ import absolute_import
  import numpy
  from mxnet import gluon
label_desc: Use image node_id 2 for calling a global function with example usage: _generate_base_anchors(base_size, scales, aspect_ratios) and returns: anchors