code: def _randomize_single_subject(data, seed=None):
      """Randomly permute the voxels of the subject.
  
       The subject is organized as Voxel x TR,
       this method shuffles the voxel dimension in place.
  
      Parameters
      ----------
      data: 2D array in shape [nVoxels, nTRs]
          Activity image data to be shuffled.
      seed: Optional[int]
          Seed for random state used implicitly for shuffling.
  
      Returns
      -------
      None.
      """
      if seed is not None:
          np.random.seed(seed)
      np.random.shuffle(data)
  
file_path: brainiak/brainiak/fcma/preprocessing.py
imports: import math
  import time
  import numpy
  import logging
  from scipy.stats.mstats import zscore
  from mpi4py import MPI
  from enum import Enum
  from ..image import mask_images, multimask_images
label_desc: Use image node_id 2 for calling a global function with example usage: _randomize_single_subject(data, seed) without return types