code: def mean_absolute_difference(a, b):
      """Mean absolute difference between two arrays.
  
      Parameters
      ----------
      a : numpy.ndarray
          Input 1d array.
      b : numpy.ndarray
          Input 1d array.
  
      Returns
      -------
      float
          mean(abs(a - b)).
  
      """
      return np.mean(np.abs(a - b))
  
imports: import logging
  import unittest
  import numpy
  from numpy.testing import assert_array_equal
  from scipy import sparse
  from scipy.sparse import csc_matrix
  from scipy.special import psi
  import gensim.matutils
label_desc: Use image node_id 2 for calling a global function with example usage: mean_absolute_difference(a, b) and returns: np