code: def testIdentifyGradientWorksOnMultipleLosses(self):
      grad_debugger_1 = debug_gradients.GradientsDebugger()
      grad_debugger_2 = debug_gradients.GradientsDebugger()
  
      y = math_ops.add(self.w, -1.0, name="y")
      debug_y = grad_debugger_1.identify_gradient(y)
      z1 = math_ops.square(debug_y, name="z1")
  
      debug_y = grad_debugger_2.identify_gradient(y)
      z2 = math_ops.sqrt(debug_y, name="z2")
  
      with grad_debugger_1:
          gradient_descent.GradientDescentOptimizer(0.1).minimize(z1)
      with grad_debugger_2:
          gradient_descent.GradientDescentOptimizer(0.1).minimize(z2)
  
      dz1_dy = grad_debugger_1.gradient_tensor(y)
      dz2_dy = grad_debugger_2.gradient_tensor(y)
      self.assertIsInstance(dz1_dy, tensor.Tensor)
      self.assertIsInstance(dz2_dy, tensor.Tensor)
      self.assertIsNot(dz1_dy, dz2_dy)
  
      self.sess.run(variables.global_variables_initializer())
      self.assertAllClose(5.0**2, self.sess.run(z1))
      self.assertAllClose(5.0**0.5, self.sess.run(z2))
      self.assertAllClose(2.0 * 5.0, self.sess.run(dz1_dy))
      self.assertAllClose(0.5 * (5.0**-0.5), self.sess.run(dz2_dy))
  
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 6 for calling the IdentifyGradientTest obj's underlying member method code with example usage: obj.testIdentifyGradientWorksOnMultipleLosses() without return types