code: def remove_blank(labels, blank=0):
      new_labels = [x for x in labels if x != blank]
      return new_labels
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import cv2
  import math
  import numpy
  from itertools import groupby
  from skimage.morphology._skeletonize import thin
label_desc: Use image node_id 4 for calling a global function with example usage: remove_blank(labels, blank) and returns: new_labels