code: def _add_gaussian(sig, noise1, noise2):
      """
      Helper function to add_noise
  
      This one simply adds one of the Gaussians to the sig and ignores the other
      one.
      """
      return sig + noise1
  
imports: import numpy
  from numpy import dot
  from dipy.core.geometry import sphere2cart
  from dipy.core.geometry import vec2vec_rotmat
  from dipy.core.gradients import GradientTable
  from dipy.reconst.utils import dki_design_matrix
  from scipy.special import jn
label_desc: Use image node_id 2 for calling a global function with example usage: _add_gaussian(sig, noise1, noise2) and returns: unknown