code: def sigma(self) -> torch.Tensor:
      return self.log_sigma.exp()
  
imports: import numpy
  import torch
  from torch import nn
  from .None import distance
  from typing import Optional, Union, Callable
  from alibi_detect.utils.frameworks import Framework
label_desc: Use image node_id 2 for calling the GaussianRBF obj's underlying member method code with example usage: obj.sigma() and returns: self