code: def testCallingIdentifyGradientTwiceWithTheSameGradientsDebuggerErrors(
      self,
  ):
      grad_debugger = debug_gradients.GradientsDebugger()
      grad_debugger.identify_gradient(self.w)
      with self.assertRaisesRegex(
          ValueError, "The graph already contains an op named .*"
      ):
          grad_debugger.identify_gradient(self.w)
  
imports: import tempfile
  from tensorflow.core.protobuf import config_pb2
  from tensorflow.core.protobuf import rewriter_config_pb2
  from tensorflow.python.client import session
  from tensorflow.python.debug.lib import debug_data
  from tensorflow.python.debug.lib import debug_gradients
  from tensorflow.python.debug.lib import debug_utils
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import tensor
  from tensorflow.python.framework import test_util
  from tensorflow.python.lib.io import file_io
  from tensorflow.python.ops import gradients_impl
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import variables
  from tensorflow.python.platform import googletest
  from tensorflow.python.training import gradient_descent
label_desc: Use image node_id 5 for calling the IdentifyGradientTest obj's underlying member method code with example usage: obj.testCallingIdentifyGradientTwiceWithTheSameGradientsDebuggerErrors() without return types