code: def fwhm2sigma(fwhm):
      """Convert a FWHM value to sigma in a Gaussian kernel.
  
      Parameters
      ----------
      fwhm : array-like
         FWHM value or values
  
      Returns
      -------
      sigma : array or float
         sigma values corresponding to `fwhm` values
  
      Examples
      --------
      >>> sigma = fwhm2sigma(6)
      >>> sigmae = fwhm2sigma([6, 7, 8])
      >>> sigma == sigmae[0]
      True
      """
      return np.asarray(fwhm) / SIGMA2FWHM
  
file_path: nibabel/nibabel/processing.py
imports: import numpy
  import numpy.linalg
  from .optpkg import optional_package
  from .affines import AffineError, append_diag, from_matvec, rescale_affine, to_matvec
  from .imageclasses import spatial_axes_first
  from .nifti1 import Nifti1Image
  from .orientations import axcodes2ornt, io_orientation, ornt_transform
  from .spaces import vox2out_vox
label_desc: Use image node_id 1 for calling a global function with example usage: fwhm2sigma(fwhm) and returns: unknown