code: def _helper4(self, a):
      # this tests a common pattern in CuPy internal in which the host
      # operation depends on intermediate outcome on GPU (and thus requires
      # synchronization)
      result = cupy.zeros((1,), dtype=cupy.int32)
      if a.sum() > 0:  # synchronize!
          result += 1
      if a[-1] >= 0:  # synchronize!
          result += 2
      return result
  
imports: import pytest
  import cupy
  from cupy import cuda
  from cupy import testing
  import cupyx
label_desc: Use image node_id 4 for calling the TestGraph obj's underlying member method code with example usage: obj._helper4(a) and returns: result