code: def _mel_to_hertz(mel_values, name=None):
      """Converts frequencies in `mel_values` from the mel scale to linear scale.
  
      Args:
        mel_values: A `Tensor` of frequencies in the mel scale.
        name: An optional name for the operation.
  
      Returns:
        A `Tensor` of the same shape and type as `mel_values` containing linear
        scale frequencies in Hertz.
      """
      with ops.name_scope(name, "mel_to_hertz", [mel_values]):
          mel_values = ops.convert_to_tensor(mel_values)
          return _MEL_BREAK_FREQUENCY_HERTZ * (
              math_ops.exp(mel_values / _MEL_HIGH_FREQUENCY_Q) - 1.0
          )
  
file_path: tensorflow-upstream/tensorflow/python/ops/signal/mel_ops.py
imports: from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import tensor
  from tensorflow.python.framework import tensor_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops.signal import shape_ops
  from tensorflow.python.util import dispatch
  from tensorflow.python.util.tf_export import tf_export
label_desc: Use image node_id 1 for calling a global function with example usage: _mel_to_hertz(mel_values, name) and returns: unknown