code: def _check_imgs_list_list(imgs):
      """
      Check input images if they are list of list of arrays
  
      Parameters
      ----------
  
      imgs : list of list of array of shape [n_voxels, n_components]
              imgs is a list of list of arrays where element i, j of
              the array is a numpy array of shape [n_voxels, n_timeframes] that
              contains the data of subject i collected during session j.
              n_timeframes and n_voxels are assumed to be the same across
              subjects
              n_timeframes can vary across sessions
              Each voxel's timecourse is assumed to have mean 0 and variance 1
  
      Returns
      -------
      shapes: array
          Shape of input images
      """
      n_subjects = len(imgs)
  
      # Check that the number of session is not 0
      assert_non_empty_list(imgs[0], "imgs[%i]" % 0)
  
      # Check that the number of sessions is the same for all subjects
      n_sessions = None
      for i in range(len(imgs)):
          if n_sessions is None:
              n_sessions = len(imgs[i])
          if n_sessions != len(imgs[i]):
              raise ValueError(
                  "imgs[%i] has length %i whereas imgs[%i] "
                  "has length %i. All subjects should have "
                  "the same number of sessions."
                  % (i, len(imgs[i]), 0, len(imgs[0]))
              )
  
      shapes = np.zeros((n_subjects, n_sessions, 2))
      # Run array-level checks
      for i in range(len(imgs)):
          for j in range(len(imgs[i])):
              assert_array_2axis(imgs[i][j], "imgs[%i][%i]" % (i, j))
              shapes[i, j, :] = imgs[i][j].shape
  
      return shapes
  
imports: import hashlib
  import logging
  import os
  import numpy
  import scipy
  from joblib import Parallel, delayed
  from brainiak.funcalign.srm import DetSRM
  from sklearn.base import BaseEstimator, TransformerMixin
  from sklearn.exceptions import NotFittedError
  import uuid
label_desc: Use image node_id 8 for calling a global function with example usage: _check_imgs_list_list(imgs) and returns: shapes