code: def testConvertVariablesToTensors(self):
      ct = CT(1)
      result = ct._convert_variables_to_tensors()
      self.assertIs(result, ct)
  
      result2 = composite_tensor.convert_variables_to_tensors(ct)
      self.assertIs(result2, ct)
  
imports: import gc
  import sys
  import weakref
  from absl.testing import parameterized
  import numpy
  from tensorflow.python.framework import composite_tensor
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import indexed_slices
  from tensorflow.python.framework import sparse_tensor
  from tensorflow.python.framework import test_util
  from tensorflow.python.framework import type_spec
  from tensorflow.python.ops.ragged import ragged_factory_ops
  from tensorflow.python.platform import googletest
  from tensorflow.python.util import nest
label_desc: Use image node_id 15 for calling the CompositeTensorTest obj's underlying member method code with example usage: obj.testConvertVariablesToTensors() without return types