code: def disable_mixed_precision_graph_rewrite_v1():
      """Disables the mixed precision graph rewrite.
  
      After this is called, the mixed precision graph rewrite will no longer run for
      new Sessions, and so float32 operations will no longer be converted to float16
      in such Sessions. However, any existing Sessions will continue to have the
      graph rewrite enabled if they were created after
      `enable_mixed_precision_graph_rewrite` was called but before
      `disable_mixed_precision_graph_rewrite` was called.
  
      This does not undo the effects of loss scaling. Any optimizers wrapped with a
      LossScaleOptimizer will continue to do loss scaling, although this loss
      scaling will no longer be useful if the optimizer is used in new Sessions, as
      the graph rewrite no longer converts the graph to use float16.
  
      This function is useful for unit testing. A unit tests can test using the
      mixed precision graph rewrite, then disable it so future unit tests continue
      using float32. If this is done, unit tests should not share a single session,
      as `enable_mixed_precision_graph_rewrite` and
      `disable_mixed_precision_graph_rewrite` have no effect on existing sessions.
      """
      # We only have a separate V1 version of this function, because the V1
      # docstring mentions sessions.
      if (
          not mixed_precision_global_state.is_mixed_precision_graph_rewrite_enabled()
      ):
          tf_logging.warn(
              "disable_mixed_precision_graph_rewrite() called when mixed "
              "precision is already disabled."
          )
      config.set_optimizer_experimental_options(
          {"auto_mixed_precision": False}
      )
      mixed_precision_global_state.set_mixed_precision_graph_rewrite_enabled(
          False
      )
  
file_path: tensorflow/tensorflow/python/training/experimental/mixed_precision.py
imports: from tensorflow.python.framework import config
  from tensorflow.python.platform import tf_logging
  from tensorflow.python.training import optimizer
  from tensorflow.python.training.experimental import loss_scale_optimizer
  from tensorflow.python.training.experimental import mixed_precision_global_state
  from tensorflow.python.util import deprecation
  from tensorflow.python.util.tf_export import tf_export
label_desc: Use image node_id 4 for calling a global function with example usage: disable_mixed_precision_graph_rewrite_v1() without return types