class_docstr: Value approximation objective, which minimizes the L2-distance between the state-(action-)value
  estimate and the target reward value
  (specification key: `value`, `state_value`, `action_value`).
  
  Args:
      value ("state" | "action"): Whether to approximate the state- or state-action-value
          (<span style="color:#C00000"><b>required</b></span>).
      huber_loss (parameter, float > 0.0): Huber loss threshold
          (<span style="color:#00C000"><b>default</b></span>: no huber loss).
      early_reduce (bool): Whether to compute objective for aggregated value instead of value per
          action (<span style="color:#00C000"><b>default</b></span>: true).
      name (string): <span style="color:#0000C0"><b>internal use</b></span>.
      states_spec (specification): <span style="color:#0000C0"><b>internal use</b></span>.
      internals_spec (specification): <span style="color:#0000C0"><b>internal use</b></span>.
      auxiliaries_spec (specification): <span style="color:#0000C0"><b>internal use</b></span>.
      actions_spec (specification): <span style="color:#0000C0"><b>internal use</b></span>.
      reward_spec (specification): <span style="color:#0000C0"><b>internal use</b></span>.
code: def reference_spec(self):
      # if self.early_reduce:
      return TensorSpec(type="float", shape=())
  
file_path: tensorforce/tensorforce/core/objectives/value.py
imports: import tensorflow
  from tensorforce.core import parameter_modules, TensorSpec, tf_function, tf_util
  from tensorforce.core.objectives import Objective
label_desc: Use image node_id 3 for calling the Value obj's underlying member method code with example usage: obj.reference_spec() and returns: TensorSpec