code: def Dir_anis_corr(InDir, AniSpec):
      
      Dir = np.zeros((3), 'f')
      Dir[0] = InDir[0]
      Dir[1] = InDir[1]
      Dir[2] = 1.
      chi, chi_inv = check_F(AniSpec)
      if chi[0][0] == 1.:
          return Dir  # isotropic
      X = dir2cart(Dir)
      M = np.array(X)
      H = np.dot(M, chi_inv)
      return cart2dir(H)
docs: takes the 6 element 's' vector and the Dec,Inc 'InDir' data,
      performs simple anisotropy correction. returns corrected Dec, Inc