code: def intensities(image, mask=slice(None)):
      r"""Takes a simple or multi-spectral image and returns its voxel-wise intensities.
      A multi-spectral image must be supplied as a list or tuple of its spectra.
  
      Optionally a binary mask can be supplied to select the voxels for which the feature
      should be extracted.
  
      Parameters
      ----------
      image : array_like or list/tuple of array_like
          A single image or a list/tuple of images (for multi-spectral case).
      mask : array_like
          A binary mask for the image.
  
      Returns
      -------
      intensities : ndarray
          The images intensities.
      """
      return _extract_feature(_extract_intensities, image, mask)
  
imports: import numpy
  from scipy.ndimage import gaussian_filter, median_filter
  from scipy.ndimage import gaussian_gradient_magnitude
  from scipy.interpolate.interpolate import interp1d
  from scipy.ndimage import distance_transform_edt
  from scipy.ndimage._ni_support import _get_output
  from .utilities import join
  from ..core import ArgumentError
  from ..filter import sum_filter
label_desc: Use image node_id 1 for calling a global function with example usage: intensities(image, mask) and returns: _extract_feature