code: def test_str_leading_zeros(self):
      p = np.poly1d([4, 3, 2, 1])
      p[3] = 0
      assert_equal(str(p), "   2\n" "3 x + 2 x + 1")
  
      p = np.poly1d([1, 2])
      p[0] = 0
      p[1] = 0
      assert_equal(str(p), " \n0")
  
imports: import numpy
  from numpy.testing import assert_, assert_equal, assert_array_equal, assert_almost_equal, assert_array_almost_equal, assert_raises, assert_allclose
  import pytest
label_desc: Use image node_id 8 for calling the TestPolynomial obj's underlying member method code with example usage: obj.test_str_leading_zeros() without return types