code: def sigma(self) -> torch.Tensor:
      return self.log_sigma.exp()
  
imports: from pykeops.torch import LazyTensor
  import torch
  import torch.nn
  from typing import Callable, Optional, Union
  from alibi_detect.utils.frameworks import Framework
  from alibi_detect.utils._types import Literal
  from copy import deepcopy
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