class_docstr: Base class for instance masks.
class_docstr_tok: ["Base","class","for","instance","masks","."]
docstr: ndarray: areas of each instance.
docstr_tok: ["ndarray",":","areas","of","each","instance","."]
code: def areas(self):
      """ndarray: areas of each instance."""
      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 8 for calling the BaseInstanceMasks obj's underlying member method code with example usage: obj.areas() without return types