code: def iter_img(imgs):
      """Iterate over a 4D Niimg-like object in the fourth dimension.
  
      Parameters
      ----------
      imgs : 4D Niimg-like object
          See :ref:`extracting_data`.
  
      Returns
      -------
      Iterator of 3D :class:`~nibabel.nifti1.Nifti1Image`
  
      See Also
      --------
      nilearn.image.index_img
  
      """
      return check_niimg_4d(imgs, return_iterator=True)
  
imports: import collections.abc
  import copy
  import itertools
  import warnings
  import nibabel
  import numpy
  from joblib import Memory, Parallel, delayed
  from scipy.ndimage import gaussian_filter1d, generate_binary_structure, label
  from scipy.stats import scoreatpercentile
  from ..None import signal
  from .._utils import _repr_niimgs, as_ndarray, check_niimg, check_niimg_3d, check_niimg_4d, fill_doc
  from .._utils.exceptions import DimensionError
  from .._utils.helpers import rename_parameters, stringify_path
  from .._utils.niimg import _get_data, safe_get_data
  from .._utils.niimg_conversions import _index_img, check_same_fov, iter_check_niimg
  from .._utils.param_validation import check_threshold
  from .._utils.path_finding import resolve_globbing
label_desc: Use image node_id 13 for calling a global function with example usage: iter_img(imgs) and returns: check_niimg_4d