code: def area(box_mask_list):
      """Computes area of masks.
  
      Args:
        box_mask_list: np_box_mask_list.BoxMaskList holding N boxes and masks
  
      Returns:
        a numpy array with shape [N*1] representing mask areas
      """
      return np_mask_ops.area(box_mask_list.get_masks())
  
file_path: SlowFast/ava_evaluation/np_box_mask_list_ops.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import numpy
  from .None import np_box_list_ops, np_box_mask_list, np_mask_ops
label_desc: Use image node_id 2 for calling a global function with example usage: area(box_mask_list) and returns: np_mask_ops