code: def sigma(self) -> np.ndarray:
      return np.exp(self.log_sigma)
  
file_path: alibi/alibi/utils/kernel.py
imports: import numpy
  from typing import Union, Optional
  from alibi.utils.distance import squared_pairwise_distance
label_desc: Use image node_id 2 for calling the GaussianRBF obj's underlying member method code with example usage: obj.sigma() and returns: np