code: def test_assign_cvec_phas_slice(self):
      spec = cvec(1024)
      spec.phas[39:-1] = -np.pi
      assert_equal(spec.phas[0:39], 0)
      assert_equal(spec.phas[39:-1], -np.pi)
      assert_equal(spec.norm, 0)
  
imports: import numpy
  from numpy.testing import TestCase, assert_equal
  from aubio import cvec, fvec, float_type
label_desc: Use image node_id 5 for calling the aubio_cvec_test_case obj's underlying member method code with example usage: obj.test_assign_cvec_phas_slice() without return types