code: def count_from_ijv(ijv, indices=None, validate=True):
      """
      The number of labels in an 'ijv' formatted label matrix
      """
      if validate:
          _validate_ijv(ijv)
  
      if indices is None:
          indices = indices_from_ijv(ijv, validate=False)
  
      return len(indices)
  
imports: from enum import Enum
  import numpy
  from numpy.random.mtrand import RandomState
  import scipy.sparse
  import centrosome.index
label_desc: Use image node_id 9 for calling a global function with example usage: count_from_ijv(ijv, indices, validate) and returns: len