class_docstr: gen table mask 
code: def __init__(self, shrink_h_max, shrink_w_max, mask_type=0, **kwargs):
      self.shrink_h_max = 5
      self.shrink_w_max = 5
      self.mask_type = mask_type
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from __future__ import unicode_literals
  import sys
  import six
  import cv2
  import numpy
label_desc: Use image node_id 1 to create a new GenTableMask object from inherited base classes: object with example: obj = GenTableMask(shrink_h_max, shrink_w_max, mask_type)