code: def _write_checkpoint(self, sess):
      self.evaluate(variables.global_variables_initializer())
      saver = saver_lib.Saver()
      ckpt_prefix = os.path.join(self.get_temp_dir(), "model")
      saver.save(sess, ckpt_prefix, global_step=0)
  
imports: import os
  import numpy
  from tensorflow.python.checkpoint import checkpoint
  from tensorflow.python.feature_column import feature_column_lib
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import ops
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import init_ops
  from tensorflow.python.ops import variable_scope
  from tensorflow.python.ops import variables
  from tensorflow.python.platform import test
  from tensorflow.python.training import checkpoint_utils
  from tensorflow.python.training import saver
  from tensorflow.python.training import warm_starting_util
label_desc: Use image node_id 2 for calling the WarmStartingUtilTest obj's underlying member method code with example usage: obj._write_checkpoint(sess) without return types