code: def _convert_variables_to_tensors(self):
      return auto_composite_tensor.convert_variables_to_tensors(self)
  
imports: import collections
  import functools
  import tensorflow.compat.v2
  from tensorflow_probability.python.distributions import joint_distribution_sequential
  from tensorflow_probability.python.internal import auto_composite_tensor
  from tensorflow_probability.python.internal import distribution_util
label_desc: Use image node_id 3 for calling the JointDistributionNamed obj's underlying member method code with example usage: obj._convert_variables_to_tensors() and returns: auto_composite_tensor