class_docstr: Base class for instance masks.
class_docstr_tok: ["Base","class","for","instance","masks","."]
docstr: see :class:`Expand`.
docstr_tok: ["see",":","class",":","`","Expand","`","."]
code: def expand(self, expanded_h, expanded_w, top, left):
      """see :class:`Expand`."""
      pass
  
imports: from abc import ABCMeta, abstractmethod
  import cv2
  import mmcv
  import numpy
  import pycocotools.mask
  import torch
  from mmcv.ops.roi_align import roi_align
label_desc: Use image node_id 7 for calling the BaseInstanceMasks obj's underlying member method code with example usage: obj.expand(expanded_h, expanded_w, top, left) without return types