code: def test_pow(self):
      out = self.p**3
      assert_equal(out.symbol, "z")
  
imports: import pytest
  import numpy.polynomial
  from numpy._core import array
  from numpy.testing import assert_equal, assert_raises, assert_
label_desc: Use image node_id 4 for calling the TestUnaryOperators obj's underlying member method code with example usage: obj.test_pow() without return types