code: def testSparsePow(self):
      x = jnp.arange(20.0).reshape(4, 5)
      xsp = BCOO.fromdense(x)
  
      result_dense = x**2
      result_sparse = xsp**2
  
      self.assertAllClose(result_dense, result_sparse.todense())
  
      with self.assertRaisesRegex(
          NotImplementedError,
          "sparse rule for integer_pow with non-positive exponent",
      ):
          _ = xsp**-1
  
imports: from functools import partial
  import math
  import operator
  from absl.testing import absltest
  from absl.testing import parameterized
  import numpy
  import jax
  from jax import config, jit, lax
  import jax.numpy
  import jax._src.test_util
  from jax.experimental.sparse import BCOO, BCSR, sparsify, todense, SparseTracer
  from jax.experimental.sparse.transform import arrays_to_spvalues, spvalues_to_arrays, sparsify_raw, SparsifyValue, SparsifyEnv
  from jax.experimental.sparse.util import CuSparseEfficiencyWarning
  from jax.experimental.sparse import test_util
label_desc: Use image node_id 15 for calling the SparsifyTest obj's underlying member method code with example usage: obj.testSparsePow() without return types