class_docstr: Unnormalized gaussian kernel
  
  .. math::
      k(|x-y|) = \exp(-|x-y|^2/(2\ell^2))
  
  where :math:`\ell` is the `lengthscale` (autodetected or given).
code: def __init__(self, lengthscale=None):
      super().__init__()
      self.lengthscale = lengthscale
  
imports: from typing import Optional
  import torch
  from .None import Detector
  import torchdrift.utils
label_desc: Use image node_id 1 to create a new GaussianKernel object from inherited base classes: Kernel with example: obj = GaussianKernel(lengthscale)