code: def test_chebmulx(self):
      assert_equal(cheb.chebmulx([0]), [0])
      assert_equal(cheb.chebmulx([1]), [0, 1])
      for i in range(1, 5):
          ser = [0] * i + [1]
          tgt = [0] * (i - 1) + [0.5, 0, 0.5]
          assert_equal(cheb.chebmulx(ser), tgt)
  
imports: from functools import reduce
  import numpy
  import numpy.polynomial.chebyshev
  from numpy.polynomial.polynomial import polyval
  from numpy.testing import assert_almost_equal, assert_raises, assert_equal, assert_
label_desc: Use image node_id 3 for calling the TestArithmetic obj's underlying member method code with example usage: obj.test_chebmulx() without return types