class_docstr: Base class for anchor generators for the task of object detection.
docstr: Returns anchors per output stride. Child classes must implement this function.
code: def num_anchors_per_os(self):
      """Returns anchors per output stride. Child classes must implement this function."""
      raise NotImplementedError
  
file_path: ml-cvnets/cvnets/anchor_generator/base_anchor_generator.py
imports: import argparse
  from typing import Optional, Tuple, Union
  import torch
  from torch import Tensor
label_desc: Use image node_id 3 for calling the BaseAnchorGenerator obj's underlying member method code with example usage: obj.num_anchors_per_os() without return types