code: def project_hemisph_bvecs(gtab):
      """Project any near identical bvecs to the other hemisphere
  
      Parameters
      ----------
      gtab : object,
              GradientTable
  
      Notes
      -----
      Useful only when working with some types of dsi data.
      """
      bvals = gtab.bvals
      bvecs = gtab.bvecs
      bvs = bvals[1:]
      bvcs = bvecs[1:]
      b = bvs[:, None] * bvcs
      bb = np.zeros((len(bvs), len(bvs)))
      pairs = []
      for i, vec in enumerate(b):
          for j, vec2 in enumerate(b):
              bb[i, j] = np.sqrt(np.sum((vec - vec2) ** 2))
          I = np.argsort(bb[i])
          for j in I:
              if j != i:
                  break
          if (j, i) in pairs:
              pass
          else:
              pairs.append((i, j))
      bvecs2 = bvecs.copy()
      for i, j in pairs:
          bvecs2[1 + j] = -bvecs2[1 + j]
      return bvecs2, pairs
  
imports: import numpy
  from scipy.ndimage import map_coordinates
  from scipy.fftpack import fftn, fftshift, ifftshift
  from dipy.reconst.odf import OdfModel, OdfFit
  from dipy.reconst.cache import Cache
  from dipy.reconst.multi_voxel import multi_voxel_fit
label_desc: Use image node_id 7 for calling a global function with example usage: project_hemisph_bvecs(gtab) and returns: bvecs2,  pairs