code: def _helper2(self, a):
      # this tests ufuncs involving math API calls
      a = 3 * cupy.sin(a)
      return cupy.sqrt(a)
  
imports: import pytest
  import cupy
  from cupy import cuda
  from cupy import testing
  import cupyx
label_desc: Use image node_id 2 for calling the TestGraph obj's underlying member method code with example usage: obj._helper2(a) and returns: cupy