code: def test_obliquity():
      """Check the calculation of inclination of an affine axes."""
      from math import pi
  
      aligned = np.diag([2.0, 2.0, 2.3, 1.0])
      aligned[:-1, -1] = [-10, -10, -7]
      R = from_matvec(
          euler2mat(x=0.09, y=0.001, z=0.001), [0.0, 0.0, 0.0]
      )
      oblique = R.dot(aligned)
      assert_almost_equal(obliquity(aligned), [0.0, 0.0, 0.0])
      assert_almost_equal(
          obliquity(oblique) * 180 / pi,
          [0.0810285, 5.1569949, 5.1569376],
      )
  
file_path: nibabel/nibabel/tests/test_affines.py
imports: from itertools import product
  import numpy
  import pytest
  from numpy.testing import assert_almost_equal, assert_array_almost_equal, assert_array_equal
  from ..affines import AffineError, append_diag, apply_affine, dot_reduce, from_matvec, obliquity, rescale_affine, to_matvec, voxel_sizes
  from ..eulerangles import euler2mat
  from ..orientations import aff2axcodes
label_desc: Use image node_id 7 for calling a global function with example usage: test_obliquity() without return types