class_docstr: Simple bias appending layer for free_log_std.
class_docstr_tok: ["Simple","bias","appending","layer","for","free_log_std","."]
code: def __init__(self, num_bias_vars: int):
      super().__init__()
      self.log_std = torch.nn.Parameter(
          torch.as_tensor([0.0] * num_bias_vars)
      )
      self.register_parameter("log_std", self.log_std)
  
imports: import numpy
  from typing import Union, Tuple, Any, List
  from ray.rllib.models.utils import get_activation_fn
  from ray.rllib.utils.annotations import DeveloperAPI
  from ray.rllib.utils.framework import try_import_torch
  from ray.rllib.utils.typing import TensorType
label_desc: Use image node_id 1 to create a new AppendBiasLayer object from inherited base classes: nn with example: obj = AppendBiasLayer(num_bias_vars)